diff --git a/.github/workflows/e2e-tests.yml b/.github/workflows/e2e-tests.yml
index 8624ee7a07..ae50d87f53 100644
--- a/.github/workflows/e2e-tests.yml
+++ b/.github/workflows/e2e-tests.yml
@@ -33,7 +33,7 @@ jobs:
     secrets: inherit
 
   test-e2e:
-    name: "${{ matrix.test.name }}${{ matrix.test.type == 'orbit-eth' && ' with L3' || matrix.test.type == 'orbit-custom' && ' with custom fee token' || ''}}"
+    name: "Test E2E - ${{ matrix.test.name }} ${{ matrix.test.typeName }}"
     needs: [build, load-e2e-files]
     runs-on: ubuntu-latest
     strategy:
@@ -100,16 +100,25 @@ jobs:
           nitro-testnode-ref: badbcbea9b43d46e115da4d7c9f2f57c31af8431
           l3-node: ${{ matrix.test.type != 'regular' }}
           no-l3-token-bridge: ${{ matrix.test.type == 'regular' }}
-          args: ${{ matrix.test.type == 'orbit-custom' && '--l3-fee-token' || '' }}
+          args: >-
+            ${{
+              (matrix.test.type == 'orbit-eth') && '--l3node --l3-token-bridge' ||
+              (matrix.test.type == 'orbit-custom-6dec' && '--l3-fee-token --l3-fee-token-decimals 6') ||
+              (matrix.test.type == 'orbit-custom-18dec' && '--l3-fee-token') ||
+              (matrix.test.type == 'orbit-custom-20dec' && '--l3-fee-token --l3-fee-token-decimals 20') ||
+              ''
+            }}
 
       - name: Run e2e tests via cypress-io/github-action
         uses: cypress-io/github-action@0da3c06ed8217b912deea9d8ee69630baed1737e # pin@v6.7.6
         with:
           start: yarn start
           command: >-
-            ${{ 
+            ${{
               (matrix.test.type == 'orbit-eth') && 'yarn test:e2e:orbit --browser chrome' ||
-              (matrix.test.type == 'orbit-custom' && 'yarn test:e2e:orbit:custom-gas-token --browser chrome') ||
+              (matrix.test.type == 'orbit-custom-6dec' && 'yarn test:e2e:orbit:custom-gas-token --browser chrome') ||
+              (matrix.test.type == 'orbit-custom-18dec' && 'yarn test:e2e:orbit:custom-gas-token --browser chrome') ||
+              (matrix.test.type == 'orbit-custom-20dec' && 'yarn test:e2e:orbit:custom-gas-token --browser chrome') ||
               (matrix.test.type == 'cctp' && 'yarn test:e2e:cctp --browser chrome') ||
               'yarn test:e2e --browser chrome'
             }}
@@ -134,7 +143,7 @@ jobs:
         uses: actions/upload-artifact@v4
         if: always()
         with:
-          name: e2e-artifacts-${{ github.sha }}-${{ matrix.test.name }}-${{ (matrix.test.type == 'cctp' && 'cctp') || (matrix.test.type == 'orbit-eth' && 'l3') || (matrix.test.type == 'orbit-custom' && 'custom-fee-token') || 'regular'}}
+          name: e2e-artifacts-${{ github.sha }}-${{ matrix.test.name }}-${{ matrix.test.type }}
           path: |
             ./packages/arb-token-bridge-ui/cypress/videos
             ./packages/arb-token-bridge-ui/cypress/screenshots
diff --git a/.github/workflows/formatSpecfiles.js b/.github/workflows/formatSpecfiles.js
index bb6b23e1ef..3d1976daae 100644
--- a/.github/workflows/formatSpecfiles.js
+++ b/.github/workflows/formatSpecfiles.js
@@ -11,14 +11,27 @@ switch (testType) {
       tests.push({
         ...spec,
         type: "regular",
+        typeName: "",
       });
       tests.push({
         ...spec,
         type: "orbit-eth",
+        typeName: "with L3 (ETH)",
       });
       tests.push({
         ...spec,
-        type: "orbit-custom",
+        type: "orbit-custom-6dec",
+        typeName: "with L3 (6 decimals custom)",
+      });
+      tests.push({
+        ...spec,
+        type: "orbit-custom-18dec",
+        typeName: "with L3 (18 decimals custom)",
+      });
+      tests.push({
+        ...spec,
+        type: "orbit-custom-20dec",
+        typeName: "with L3 (20 decimals custom)",
       });
     });
     break;
@@ -27,6 +40,7 @@ switch (testType) {
     // Running CCTP tests in parallel cause nonce issues, we're running the two tests sequentially
     tests.push({
       name: "cctp",
+      typeName: "",
       file: "tests/e2e/specs/**/*Cctp.cy.{js,jsx,ts,tsx}",
       recordVideo: false,
       type: "cctp",
diff --git a/packages/arb-token-bridge-ui/package.json b/packages/arb-token-bridge-ui/package.json
index 6e272c5df7..e8d292c70b 100644
--- a/packages/arb-token-bridge-ui/package.json
+++ b/packages/arb-token-bridge-ui/package.json
@@ -5,7 +5,7 @@
   "private": true,
   "dependencies": {
     "@apollo/client": "^3.7.11",
-    "@arbitrum/sdk": "^4.0.1",
+    "@arbitrum/sdk": "^4.0.2-beta.1",
     "@ethersproject/providers": "^5.7.0",
     "@headlessui/react": "^1.7.8",
     "@headlessui/tailwindcss": "^0.1.2",
diff --git a/packages/arb-token-bridge-ui/src/components/TransferPanel/TokenRow.tsx b/packages/arb-token-bridge-ui/src/components/TransferPanel/TokenRow.tsx
index 6017331763..3cc1bbe3d2 100644
--- a/packages/arb-token-bridge-ui/src/components/TransferPanel/TokenRow.tsx
+++ b/packages/arb-token-bridge-ui/src/components/TransferPanel/TokenRow.tsx
@@ -32,6 +32,7 @@ import { useNetworks } from '../../hooks/useNetworks'
 import { useNetworksRelationship } from '../../hooks/useNetworksRelationship'
 import { TokenLogoFallback } from './TokenInfo'
 import { useBalanceOnSourceChain } from '../../hooks/useBalanceOnSourceChain'
+import { useNativeCurrencyDecimalsOnSourceChain } from '../../hooks/useNativeCurrencyDecimalsOnSourceChain'
 
 function tokenListIdsToNames(ids: number[]): string {
   return ids
@@ -244,6 +245,8 @@ function TokenBalance({ token }: { token: ERC20BridgeToken | null }) {
   } = useAppState()
   const { isLoading: isLoadingAccountType } = useAccountType()
   const { balance, symbol } = useTokenInfo(token)
+  const nativeCurrencyDecimalsOnSourceChain =
+    useNativeCurrencyDecimalsOnSourceChain()
 
   const isArbitrumNativeUSDC =
     isTokenArbitrumOneNativeUSDC(token?.address) ||
@@ -266,6 +269,13 @@ function TokenBalance({ token }: { token: ERC20BridgeToken | null }) {
     return typeof bridgeTokens[token.address] !== 'undefined'
   }, [bridgeTokens, isArbitrumNativeUSDC, token])
 
+  const decimals = useMemo(() => {
+    if (token) {
+      return token.decimals
+    }
+    return nativeCurrencyDecimalsOnSourceChain
+  }, [nativeCurrencyDecimalsOnSourceChain, token])
+
   if (!tokenIsAddedToTheBridge) {
     return <span className="arb-hover text-sm">Import</span>
   }
@@ -279,7 +289,7 @@ function TokenBalance({ token }: { token: ERC20BridgeToken | null }) {
     <span className="flex items-center whitespace-nowrap text-sm text-white/70">
       {balance ? (
         formatAmount(balance, {
-          decimals: token?.decimals,
+          decimals,
           symbol
         })
       ) : (
diff --git a/packages/arb-token-bridge-ui/src/components/TransferPanel/TransferPanel.tsx b/packages/arb-token-bridge-ui/src/components/TransferPanel/TransferPanel.tsx
index 74c4a4c788..a631d602f7 100644
--- a/packages/arb-token-bridge-ui/src/components/TransferPanel/TransferPanel.tsx
+++ b/packages/arb-token-bridge-ui/src/components/TransferPanel/TransferPanel.tsx
@@ -6,6 +6,7 @@ import { useLatest } from 'react-use'
 import { useAccount, useNetwork, useSigner } from 'wagmi'
 import { TransactionResponse } from '@ethersproject/providers'
 import { twMerge } from 'tailwind-merge'
+import { scaleFrom18DecimalsToNativeTokenDecimals } from '@arbitrum/sdk'
 
 import { useAppState } from '../../state'
 import { getNetworkName, isNetwork } from '../../util/networks'
@@ -77,6 +78,7 @@ import { useIsTransferAllowed } from './hooks/useIsTransferAllowed'
 import { MoveFundsButton } from './MoveFundsButton'
 import { ProjectsListing } from '../common/ProjectsListing'
 import { useAmountBigNumber } from './hooks/useAmountBigNumber'
+import { useNativeCurrencyDecimalsOnSourceChain } from '../../hooks/useNativeCurrencyDecimalsOnSourceChain'
 
 const signerUndefinedError = 'Signer is undefined'
 const transferNotAllowedError = 'Transfer not allowed'
@@ -131,6 +133,8 @@ export function TransferPanel() {
     }
   } = useLatest(useNetworksRelationship(latestNetworks.current))
   const isBatchTransferSupported = useIsBatchTransferSupported()
+  const nativeCurrencyDecimalsOnSourceChain =
+    useNativeCurrencyDecimalsOnSourceChain()
 
   const nativeCurrency = useNativeCurrency({ provider: childChainProvider })
 
@@ -616,7 +620,7 @@ export function TransferPanel() {
           amount: amountBigNumber,
           options: {
             approvalAmountIncrease: isCustomNativeTokenAmount2
-              ? utils.parseUnits(amount2, nativeCurrency.decimals)
+              ? utils.parseUnits(amount2, nativeCurrencyDecimalsOnSourceChain)
               : undefined
           }
         })
@@ -631,7 +635,7 @@ export function TransferPanel() {
           amount: amountBigNumber,
           options: {
             approvalAmountIncrease: isCustomNativeTokenAmount2
-              ? utils.parseUnits(amount2, nativeCurrency.decimals)
+              ? utils.parseUnits(amount2, nativeCurrencyDecimalsOnSourceChain)
               : undefined
           }
         })
@@ -744,6 +748,7 @@ export function TransferPanel() {
         }
 
         overrides.maxSubmissionCost = utils
+          // we are not scaling these to native decimals because arbitrum-sdk does it for us
           .parseEther(amount2)
           .add(gasEstimates.estimatedChildChainSubmissionCost)
         overrides.excessFeeRefundAddress = destinationAddress
@@ -798,6 +803,20 @@ export function TransferPanel() {
 
     const timestampCreated = String(normalizeTimestamp(Date.now()))
 
+    const { isOrbitChain: isSourceOrbitChain } = isNetwork(
+      latestNetworks.current.sourceChain.id
+    )
+
+    const scaledAmount =
+      // only scale for native tokens, and
+      // only scale if sent from Orbit, because it's always 18 decimals there but the UI needs scaled amount
+      selectedToken || !isSourceOrbitChain
+        ? amountBigNumber
+        : scaleFrom18DecimalsToNativeTokenDecimals({
+            amount: amountBigNumber,
+            decimals: nativeCurrency.decimals
+          })
+
     const txHistoryCompatibleObject = convertBridgeSdkToMergedTransaction({
       bridgeTransfer,
       parentChainId: parentChain.id,
@@ -806,7 +825,7 @@ export function TransferPanel() {
       walletAddress,
       destinationAddress,
       nativeCurrency,
-      amount: amountBigNumber,
+      amount: scaledAmount,
       amount2: isBatchTransfer ? utils.parseEther(amount2) : undefined,
       timestampCreated
     })
@@ -825,7 +844,7 @@ export function TransferPanel() {
           walletAddress,
           destinationAddress,
           nativeCurrency,
-          amount: amountBigNumber,
+          amount: scaledAmount,
           amount2: isBatchTransfer ? utils.parseEther(amount2) : undefined,
           timestampCreated
         })
diff --git a/packages/arb-token-bridge-ui/src/components/TransferPanel/TransferPanelMain/SourceNetworkBox.tsx b/packages/arb-token-bridge-ui/src/components/TransferPanel/TransferPanelMain/SourceNetworkBox.tsx
index 48d493e25c..36f858e22d 100644
--- a/packages/arb-token-bridge-ui/src/components/TransferPanel/TransferPanelMain/SourceNetworkBox.tsx
+++ b/packages/arb-token-bridge-ui/src/components/TransferPanel/TransferPanelMain/SourceNetworkBox.tsx
@@ -33,6 +33,7 @@ import { Button } from '../../common/Button'
 import { useSelectedTokenDecimals } from '../../../hooks/TransferPanel/useSelectedTokenDecimals'
 import { useNativeCurrencyBalances } from './useNativeCurrencyBalances'
 import { useIsCctpTransfer } from '../hooks/useIsCctpTransfer'
+import { useNativeCurrencyDecimalsOnSourceChain } from '../../../hooks/useNativeCurrencyDecimalsOnSourceChain'
 
 function Amount2ToggleButton({
   onClick
@@ -92,6 +93,8 @@ export function SourceNetworkBox() {
   const decimals = useSelectedTokenDecimals()
   const { errorMessages } = useTransferReadiness()
   const nativeCurrencyBalances = useNativeCurrencyBalances()
+  const nativeCurrencyDecimalsOnSourceChain =
+    useNativeCurrencyDecimalsOnSourceChain()
 
   const isCctpTransfer = useIsCctpTransfer()
 
@@ -145,10 +148,19 @@ export function SourceNetworkBox() {
       symbol: nativeCurrency.symbol,
       disabled: true,
       balance: nativeCurrencyBalances.sourceBalance
-        ? Number(utils.formatEther(nativeCurrencyBalances.sourceBalance))
+        ? Number(
+            utils.formatUnits(
+              nativeCurrencyBalances.sourceBalance,
+              nativeCurrencyDecimalsOnSourceChain
+            )
+          )
         : undefined
     }),
-    [nativeCurrencyBalances, nativeCurrency.symbol]
+    [
+      nativeCurrencyBalances,
+      nativeCurrency.symbol,
+      nativeCurrencyDecimalsOnSourceChain
+    ]
   )
 
   return (
diff --git a/packages/arb-token-bridge-ui/src/components/TransferPanel/TransferPanelMain/TokenBalance.tsx b/packages/arb-token-bridge-ui/src/components/TransferPanel/TransferPanelMain/TokenBalance.tsx
index 1e56d31e81..24f66b7437 100644
--- a/packages/arb-token-bridge-ui/src/components/TransferPanel/TransferPanelMain/TokenBalance.tsx
+++ b/packages/arb-token-bridge-ui/src/components/TransferPanel/TransferPanelMain/TokenBalance.tsx
@@ -1,12 +1,18 @@
+import { useMemo } from 'react'
 import { BigNumber } from 'ethers'
 
 import { ERC20BridgeToken } from '../../../hooks/arbTokenBridge.types'
-import { NativeCurrencyErc20 } from '../../../hooks/useNativeCurrency'
+import {
+  NativeCurrencyErc20,
+  useNativeCurrency
+} from '../../../hooks/useNativeCurrency'
 import { Loader } from '../../common/atoms/Loader'
 import { TokenSymbolWithExplorerLink } from '../../common/TokenSymbolWithExplorerLink'
 import { formatAmount } from '../../../util/NumberUtils'
 
 import { NetworkType } from './utils'
+import { useNetworks } from '../../../hooks/useNetworks'
+import { useNetworksRelationship } from '../../../hooks/useNetworksRelationship'
 
 export function TokenBalance({
   forToken,
@@ -22,6 +28,23 @@ export function TokenBalance({
   tokenSymbolOverride?: string
 }) {
   const isParentChain = on === NetworkType.parentChain
+  const [networks] = useNetworks()
+  const { childChainProvider } = useNetworksRelationship(networks)
+  const nativeCurrency = useNativeCurrency({
+    provider: childChainProvider
+  })
+
+  const isCustomNativeCurrency =
+    nativeCurrency.isCustom &&
+    forToken?.address.toLowerCase() === nativeCurrency.address.toLowerCase()
+
+  const decimals = useMemo(() => {
+    if (!isParentChain && isCustomNativeCurrency) {
+      // Native currency on Orbit chain, always 18 decimals
+      return 18
+    }
+    return forToken?.decimals
+  }, [forToken?.decimals, isCustomNativeCurrency, isParentChain])
 
   if (!forToken) {
     return null
@@ -43,7 +66,7 @@ export function TokenBalance({
       <span className="font-light">{prefix}</span>
       <span aria-label={`${tokenSymbol} balance amount on ${on}`}>
         {formatAmount(balance, {
-          decimals: forToken.decimals
+          decimals
         })}
       </span>{' '}
       <TokenSymbolWithExplorerLink
diff --git a/packages/arb-token-bridge-ui/src/components/TransferPanel/TransferPanelMain/useMaxAmount.ts b/packages/arb-token-bridge-ui/src/components/TransferPanel/TransferPanelMain/useMaxAmount.ts
index a40404b5ff..f033c91313 100644
--- a/packages/arb-token-bridge-ui/src/components/TransferPanel/TransferPanelMain/useMaxAmount.ts
+++ b/packages/arb-token-bridge-ui/src/components/TransferPanel/TransferPanelMain/useMaxAmount.ts
@@ -9,6 +9,7 @@ import { defaultErc20Decimals } from '../../../defaults'
 import { useGasSummary } from '../../../hooks/TransferPanel/useGasSummary'
 import { useNativeCurrency } from '../../../hooks/useNativeCurrency'
 import { useNativeCurrencyBalances } from './useNativeCurrencyBalances'
+import { useNativeCurrencyDecimalsOnSourceChain } from '../../../hooks/useNativeCurrencyDecimalsOnSourceChain'
 
 export function useMaxAmount() {
   const {
@@ -19,6 +20,8 @@ export function useMaxAmount() {
   const { childChainProvider, isDepositMode } =
     useNetworksRelationship(networks)
   const nativeCurrency = useNativeCurrency({ provider: childChainProvider })
+  const nativeCurrencyDecimalsOnSourceChain =
+    useNativeCurrencyDecimalsOnSourceChain()
 
   const { estimatedParentChainGasFees, estimatedChildChainGasFees } =
     useGasSummary()
@@ -36,14 +39,14 @@ export function useMaxAmount() {
     if (nativeCurrency.isCustom && isDepositMode) {
       return utils.formatUnits(
         nativeCurrencySourceBalance,
-        nativeCurrency.decimals
+        nativeCurrencyDecimalsOnSourceChain
       )
     }
 
     // ETH deposits and ETH/custom fee token withdrawals
     const nativeCurrencyBalanceFormatted = utils.formatUnits(
       nativeCurrencySourceBalance,
-      nativeCurrency.decimals
+      nativeCurrencyDecimalsOnSourceChain
     )
 
     if (
@@ -70,9 +73,9 @@ export function useMaxAmount() {
     estimatedChildChainGasFees,
     estimatedParentChainGasFees,
     isDepositMode,
-    nativeCurrency.decimals,
     nativeCurrency.isCustom,
-    nativeCurrencyBalances.sourceBalance
+    nativeCurrencyBalances.sourceBalance,
+    nativeCurrencyDecimalsOnSourceChain
   ])
 
   const maxAmount = useMemo(() => {
diff --git a/packages/arb-token-bridge-ui/src/components/TransferPanel/TransferPanelMainInput.tsx b/packages/arb-token-bridge-ui/src/components/TransferPanel/TransferPanelMainInput.tsx
index 414dc3303f..e6365719d6 100644
--- a/packages/arb-token-bridge-ui/src/components/TransferPanel/TransferPanelMainInput.tsx
+++ b/packages/arb-token-bridge-ui/src/components/TransferPanel/TransferPanelMainInput.tsx
@@ -21,6 +21,7 @@ import { Loader } from '../common/atoms/Loader'
 import { sanitizeAmountQueryParam } from '../../hooks/useArbQueryParams'
 import { truncateExtraDecimals } from '../../util/NumberUtils'
 import { useNativeCurrencyBalances } from './TransferPanelMain/useNativeCurrencyBalances'
+import { useSelectedTokenDecimals } from '../../hooks/TransferPanel/useSelectedTokenDecimals'
 
 function MaxButton({
   className = '',
@@ -86,6 +87,7 @@ function SourceChainTokenBalance({
   const [networks] = useNetworks()
   const { isDepositMode, childChainProvider } =
     useNetworksRelationship(networks)
+  const selectedTokenDecimals = useSelectedTokenDecimals()
 
   const nativeCurrencyBalances = useNativeCurrencyBalances()
   const selectedTokenBalances = useSelectedTokenBalances()
@@ -103,7 +105,7 @@ function SourceChainTokenBalance({
   const formattedBalance =
     balance !== null
       ? formatAmount(balance, {
-          decimals: selectedToken?.decimals ?? nativeCurrency.decimals
+          decimals: selectedTokenDecimals
         })
       : null
 
diff --git a/packages/arb-token-bridge-ui/src/components/TransferPanel/hooks/useAmountBigNumber.ts b/packages/arb-token-bridge-ui/src/components/TransferPanel/hooks/useAmountBigNumber.ts
index eb25a1680e..d578996588 100644
--- a/packages/arb-token-bridge-ui/src/components/TransferPanel/hooks/useAmountBigNumber.ts
+++ b/packages/arb-token-bridge-ui/src/components/TransferPanel/hooks/useAmountBigNumber.ts
@@ -2,18 +2,15 @@ import { useMemo } from 'react'
 import { useArbQueryParams } from '../../../hooks/useArbQueryParams'
 import { useAppState } from '../../../state'
 import { constants, utils } from 'ethers'
-import { useNetworks } from '../../../hooks/useNetworks'
-import { useNetworksRelationship } from '../../../hooks/useNetworksRelationship'
-import { useNativeCurrency } from '../../../hooks/useNativeCurrency'
+import { useNativeCurrencyDecimalsOnSourceChain } from '../../../hooks/useNativeCurrencyDecimalsOnSourceChain'
 
 export function useAmountBigNumber() {
   const {
     app: { selectedToken }
   } = useAppState()
   const [{ amount }] = useArbQueryParams()
-  const [networks] = useNetworks()
-  const { childChainProvider } = useNetworksRelationship(networks)
-  const nativeCurrency = useNativeCurrency({ provider: childChainProvider })
+  const nativeCurrencyDecimalsOnSourceChain =
+    useNativeCurrencyDecimalsOnSourceChain()
 
   return useMemo(() => {
     try {
@@ -23,9 +20,9 @@ export function useAmountBigNumber() {
         return utils.parseUnits(amountSafe, selectedToken.decimals)
       }
 
-      return utils.parseUnits(amountSafe, nativeCurrency.decimals)
+      return utils.parseUnits(amountSafe, nativeCurrencyDecimalsOnSourceChain)
     } catch (error) {
       return constants.Zero
     }
-  }, [amount, selectedToken, nativeCurrency])
+  }, [amount, selectedToken, nativeCurrencyDecimalsOnSourceChain])
 }
diff --git a/packages/arb-token-bridge-ui/src/hooks/TransferPanel/useSelectedTokenDecimals.ts b/packages/arb-token-bridge-ui/src/hooks/TransferPanel/useSelectedTokenDecimals.ts
index 13a59dd41f..c17b8fa1cd 100644
--- a/packages/arb-token-bridge-ui/src/hooks/TransferPanel/useSelectedTokenDecimals.ts
+++ b/packages/arb-token-bridge-ui/src/hooks/TransferPanel/useSelectedTokenDecimals.ts
@@ -1,16 +1,14 @@
 import { useAppState } from '../../state'
-import { useNativeCurrency } from '../useNativeCurrency'
-import { useNetworksRelationship } from '../useNetworksRelationship'
-import { useNetworks } from '../useNetworks'
+import { useNativeCurrencyDecimalsOnSourceChain } from '../useNativeCurrencyDecimalsOnSourceChain'
 
 export function useSelectedTokenDecimals() {
   const {
     app: { selectedToken }
   } = useAppState()
-  const [networks] = useNetworks()
-  const { childChainProvider } = useNetworksRelationship(networks)
+  const nativeCurrencyDecimalsOnSourceChain =
+    useNativeCurrencyDecimalsOnSourceChain()
 
-  const nativeCurrency = useNativeCurrency({ provider: childChainProvider })
-
-  return selectedToken ? selectedToken.decimals : nativeCurrency.decimals
+  return selectedToken
+    ? selectedToken.decimals
+    : nativeCurrencyDecimalsOnSourceChain
 }
diff --git a/packages/arb-token-bridge-ui/src/hooks/useNativeCurrencyDecimalsOnSourceChain.ts b/packages/arb-token-bridge-ui/src/hooks/useNativeCurrencyDecimalsOnSourceChain.ts
new file mode 100644
index 0000000000..d03aba45ea
--- /dev/null
+++ b/packages/arb-token-bridge-ui/src/hooks/useNativeCurrencyDecimalsOnSourceChain.ts
@@ -0,0 +1,21 @@
+import { isNetwork } from '../util/networks'
+import { useNativeCurrency } from './useNativeCurrency'
+import { useNetworks } from './useNetworks'
+import { useNetworksRelationship } from './useNetworksRelationship'
+
+export const useNativeCurrencyDecimalsOnSourceChain = () => {
+  const [networks] = useNetworks()
+  const { childChainProvider } = useNetworksRelationship(networks)
+  const nativeCurrency = useNativeCurrency({
+    provider: childChainProvider
+  })
+  const { isOrbitChain: isSourceChainOrbit } = isNetwork(
+    networks.sourceChain.id
+  )
+
+  if (isSourceChainOrbit) {
+    return 18
+  }
+
+  return nativeCurrency.decimals
+}
diff --git a/packages/arb-token-bridge-ui/src/token-bridge-sdk/Erc20DepositStarter.ts b/packages/arb-token-bridge-ui/src/token-bridge-sdk/Erc20DepositStarter.ts
index 3934103f21..a5f5200cbe 100644
--- a/packages/arb-token-bridge-ui/src/token-bridge-sdk/Erc20DepositStarter.ts
+++ b/packages/arb-token-bridge-ui/src/token-bridge-sdk/Erc20DepositStarter.ts
@@ -1,4 +1,7 @@
-import { Erc20Bridger } from '@arbitrum/sdk'
+import {
+  Erc20Bridger,
+  scaleFrom18DecimalsToNativeTokenDecimals
+} from '@arbitrum/sdk'
 import { BigNumber, constants, utils } from 'ethers'
 import { ERC20__factory } from '@arbitrum/sdk/dist/lib/abi/factories/ERC20__factory'
 import {
@@ -121,10 +124,12 @@ export class Erc20DepositStarter extends BridgeTransferStarter {
           .add(gasEstimates.estimatedChildChainSubmissionCost)
       )
     )
-    const estimatedDestinationChainGasFee = utils.parseUnits(
-      String(estimatedDestinationChainGasFeeEth),
-      await nativeCurrency.decimals()
-    )
+
+    const estimatedDestinationChainGasFee =
+      scaleFrom18DecimalsToNativeTokenDecimals({
+        amount: utils.parseEther(String(estimatedDestinationChainGasFeeEth)),
+        decimals: await nativeCurrency.decimals()
+      })
 
     // We want to bridge a certain amount of an ERC-20 token, but the Retryable fees on the destination chain will be paid in the custom fee token
     // We have to check if the native-token spending allowance is enough to cover the fees
@@ -194,10 +199,11 @@ export class Erc20DepositStarter extends BridgeTransferStarter {
       )
     )
 
-    const estimatedDestinationChainGasFee = utils.parseUnits(
-      String(estimatedDestinationChainGasFeeEth),
-      await nativeCurrency.decimals()
-    )
+    const estimatedDestinationChainGasFee =
+      scaleFrom18DecimalsToNativeTokenDecimals({
+        amount: utils.parseEther(String(estimatedDestinationChainGasFeeEth)),
+        decimals: await nativeCurrency.decimals()
+      })
 
     return erc20Bridger.approveGasToken({
       erc20ParentAddress: this.sourceChainErc20Address,
diff --git a/packages/arb-token-bridge-ui/src/util/withdrawals/helpers.ts b/packages/arb-token-bridge-ui/src/util/withdrawals/helpers.ts
index 82e7706695..89ab0369be 100644
--- a/packages/arb-token-bridge-ui/src/util/withdrawals/helpers.ts
+++ b/packages/arb-token-bridge-ui/src/util/withdrawals/helpers.ts
@@ -3,7 +3,8 @@ import { Provider } from '@ethersproject/providers'
 import { BigNumber } from '@ethersproject/bignumber'
 import {
   ChildToParentMessageReader,
-  ChildTransactionReceipt
+  ChildTransactionReceipt,
+  scaleFrom18DecimalsToNativeTokenDecimals
 } from '@arbitrum/sdk'
 import { FetchWithdrawalsFromSubgraphResult } from './fetchWithdrawalsFromSubgraph'
 import { fetchErc20Data } from '../TokenUtils'
@@ -87,7 +88,10 @@ export async function mapETHWithdrawalToL2ToL1EventResult({
     sender: event.caller,
     destinationAddress: event.destination,
     type: AssetType.ETH,
-    value: callvalue,
+    value: scaleFrom18DecimalsToNativeTokenDecimals({
+      amount: callvalue,
+      decimals: nativeCurrency.decimals
+    }),
     symbol: nativeCurrency.symbol,
     outgoingMessageState,
     l2TxHash: event.l2TxHash || event.transactionHash,
@@ -314,7 +318,10 @@ export async function mapWithdrawalToL2ToL1EventResult({
     sender: withdrawal.sender,
     destinationAddress: withdrawal.receiver,
     type: AssetType.ETH,
-    value: BigNumber.from(withdrawal.ethValue),
+    value: scaleFrom18DecimalsToNativeTokenDecimals({
+      amount: BigNumber.from(withdrawal.ethValue),
+      decimals: nativeCurrency.decimals
+    }),
     outgoingMessageState,
     l2TxHash: l2TxReceipt.transactionHash,
     symbol: nativeCurrency.symbol,
diff --git a/packages/arb-token-bridge-ui/synpress.config.ts b/packages/arb-token-bridge-ui/synpress.config.ts
index 2150d747e3..84a332c1b0 100644
--- a/packages/arb-token-bridge-ui/synpress.config.ts
+++ b/packages/arb-token-bridge-ui/synpress.config.ts
@@ -25,7 +25,8 @@ import {
   getCustomDestinationAddress,
   ERC20TokenSymbol,
   ERC20TokenDecimals,
-  ERC20TokenName
+  ERC20TokenName,
+  getNativeTokenDecimals
 } from './tests/support/common'
 
 import {
@@ -200,6 +201,10 @@ export default defineConfig({
       config.env.ORBIT_TEST = isOrbitTest ? '1' : '0'
       config.env.NATIVE_TOKEN_SYMBOL = isCustomFeeToken ? 'TN' : 'ETH'
       config.env.NATIVE_TOKEN_ADDRESS = ethBridger.nativeToken
+      config.env.NATIVE_TOKEN_DECIMALS = await getNativeTokenDecimals({
+        parentProvider,
+        childProvider
+      })
 
       config.env.CUSTOM_DESTINATION_ADDRESS =
         await getCustomDestinationAddress()
@@ -297,6 +302,10 @@ async function approveCustomFeeToken({
 
 async function fundUserWalletNativeCurrency() {
   const childEthBridger = await EthBridger.fromProvider(childProvider)
+  const decimals = await getNativeTokenDecimals({
+    parentProvider,
+    childProvider
+  })
 
   const address = await userWallet.getAddress()
 
@@ -306,18 +315,21 @@ async function fundUserWalletNativeCurrency() {
   )
 
   const userBalance = await tokenContract.balanceOf(address)
-  const shouldFund = userBalance.lt(utils.parseEther('0.3'))
+  const shouldFund = userBalance.lt(utils.parseUnits('0.3', decimals))
 
   if (!shouldFund) {
     console.log(
-      `User wallet has enough L3 native currency for testing, skip funding...`
+      `User wallet has enough custom native currency for testing, skip funding...`
     )
     return
   }
 
   console.log(`Funding native currency to user wallet on L2...`)
 
-  const tx = await tokenContract.transfer(address, utils.parseEther('3'))
+  const tx = await tokenContract.transfer(
+    address,
+    utils.parseUnits('3', decimals)
+  )
   await tx.wait()
 }
 
diff --git a/packages/arb-token-bridge-ui/tests/e2e/specs/login.cy.ts b/packages/arb-token-bridge-ui/tests/e2e/specs/login.cy.ts
index 5c627e2344..ce8413b0cc 100644
--- a/packages/arb-token-bridge-ui/tests/e2e/specs/login.cy.ts
+++ b/packages/arb-token-bridge-ui/tests/e2e/specs/login.cy.ts
@@ -16,6 +16,7 @@ describe('Login Account', () => {
   let l2ETHbal
 
   const nativeTokenSymbol = Cypress.env('NATIVE_TOKEN_SYMBOL')
+  const nativeTokenDecimals = Cypress.env('NATIVE_TOKEN_DECIMALS')
   const isCustomFeeToken = nativeTokenSymbol !== 'ETH'
 
   before(() => {
@@ -25,7 +26,9 @@ describe('Login Account', () => {
         multiCallerAddress: getL1NetworkConfig().multiCall,
         address: Cypress.env('ADDRESS'),
         rpcURL: Cypress.env('ETH_RPC_URL')
-      }).then(val => (l1ETHbal = formatAmount(val)))
+      }).then(
+        val => (l1ETHbal = formatAmount(val, { decimals: nativeTokenDecimals }))
+      )
     } else {
       getInitialETHBalance(Cypress.env('ETH_RPC_URL')).then(
         val => (l1ETHbal = formatAmount(val))
diff --git a/packages/arb-token-bridge-ui/tests/support/common.ts b/packages/arb-token-bridge-ui/tests/support/common.ts
index 76664a8e91..874000ada9 100644
--- a/packages/arb-token-bridge-ui/tests/support/common.ts
+++ b/packages/arb-token-bridge-ui/tests/support/common.ts
@@ -4,7 +4,7 @@
 
 import { Provider, StaticJsonRpcProvider } from '@ethersproject/providers'
 import { BigNumber, Signer, Wallet, ethers, utils } from 'ethers'
-import { MultiCaller } from '@arbitrum/sdk'
+import { EthBridger, MultiCaller } from '@arbitrum/sdk'
 import { MULTICALL_TESTNET_ADDRESS } from '../../src/constants'
 import {
   defaultL2Network,
@@ -112,7 +112,7 @@ export function getZeroToLessThanOneToken(symbol: string) {
 
 export const importTokenThroughUI = (address: string) => {
   // Click on the ETH dropdown (Select token button)
-  cy.findSelectTokenButton('ETH').click()
+  cy.findSelectTokenButton(Cypress.env('NATIVE_TOKEN_SYMBOL') ?? 'ETH').click()
 
   // open the Select Token popup
   cy.findByPlaceholderText(/Search by token name/i)
@@ -183,6 +183,28 @@ export const startWebApp = (url = '/', qs: { [s: string]: string } = {}) => {
   })
 }
 
+export async function getNativeTokenDecimals({
+  parentProvider,
+  childProvider
+}: {
+  parentProvider: Provider
+  childProvider: Provider
+}) {
+  const multiCaller = await MultiCaller.fromProvider(parentProvider)
+  const ethBridger = await EthBridger.fromProvider(childProvider)
+  const isCustomFeeToken = typeof ethBridger.nativeToken !== 'undefined'
+
+  const nativeToken = isCustomFeeToken
+    ? (
+        await multiCaller.getTokenData([ethBridger.nativeToken!], {
+          decimals: true
+        })
+      )[0]
+    : undefined
+
+  return nativeToken?.decimals ?? 18
+}
+
 export const visitAfterSomeDelay = (
   url: string,
   options?: Partial<Cypress.VisitOptions>
@@ -221,20 +243,29 @@ export async function generateActivityOnChains({
   // whilst waiting for status we mine on both parentChain and childChain
   console.log('Generating activity on parentChain...')
   const minerParent = Wallet.createRandom().connect(parentProvider)
+
+  const decimals = await getNativeTokenDecimals({
+    parentProvider,
+    childProvider
+  })
+
   await fundEth({
     address: await minerParent.getAddress(),
     provider: parentProvider,
     sourceWallet: wallet,
-    networkType: 'parentChain'
+    networkType: 'parentChain',
+    amount: utils.parseUnits('0.2', decimals)
   })
 
   console.log('Generating activity on childChain...')
   const minerChild = Wallet.createRandom().connect(childProvider)
+
   await fundEth({
     address: await minerChild.getAddress(),
     provider: childProvider,
     sourceWallet: wallet,
-    networkType: 'childChain'
+    networkType: 'childChain',
+    amount: utils.parseEther('0.2')
   })
 
   await Promise.allSettled([keepMining(minerParent), keepMining(minerChild)])
@@ -293,13 +324,13 @@ export async function fundEth({
   provider,
   sourceWallet, // source wallet that will fund the `address`,
   networkType,
-  amount = utils.parseEther('2')
+  amount
 }: {
   address: string
   provider: Provider
   sourceWallet: Wallet
   networkType: NetworkType
-  amount?: BigNumber
+  amount: BigNumber
 }) {
   console.log(`Funding ETH ${address} on ${networkType}...`)
   const balance = await provider.getBalance(address)
diff --git a/yarn.lock b/yarn.lock
index df809f5989..eba2169b8c 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -89,6 +89,17 @@
     async-mutex "^0.4.0"
     ethers "^5.1.0"
 
+"@arbitrum/sdk@^4.0.2-beta.1":
+  version "4.0.2-beta.1"
+  resolved "https://registry.yarnpkg.com/@arbitrum/sdk/-/sdk-4.0.2-beta.1.tgz#c6c6c5784a8eaa6a4edab3600f765e9f82ce5988"
+  integrity sha512-a5DG6+Ld3X4L8H3CTUl3gc27Bj/Pqjo+5UZiCI97SM2mHtHKWF1BgQ+FCk/8bgFUP5nS9dXBl5tPJRtCFfOe0A==
+  dependencies:
+    "@ethersproject/address" "^5.0.8"
+    "@ethersproject/bignumber" "^5.1.1"
+    "@ethersproject/bytes" "^5.0.8"
+    async-mutex "^0.4.0"
+    ethers "^5.1.0"
+
 "@babel/code-frame@7.12.11":
   version "7.12.11"
   resolved "https://registry.npmjs.org/@babel/code-frame/-/code-frame-7.12.11.tgz"