Cross-chain · Base → Polygon

Swap WETH from Base to POL on Polygon

Swap WETH from Base to POL on Polygon. Base WETH leaves, and native POL arrives on Polygon chain 137 today.

You approve wrapped ETH at 0x4200000000000000000000000000000000000006 on Base, chain 8453. Basescan shows that ERC-20. You receive native POL on chain 137, written as 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE. Polygonscan shows it on the account, not as a token contract. It is not Polygon WETH at 0x7ceB23fD6bC0adD59E62ac25578270cFf1b9f619. Unwrapping on Base would have returned ETH on Base, which cannot pay Polygon fees. This route is how you turn the wrapper into the destination gas coin.

Diagram for Swap WETH from Base to POL on Polygon
WETH leaves Base. POL is what can arrive on Polygon.

You are buying the fee coin

POL can pay for later Polygon transactions. The amount is the quote, not a calculated reserve. A small fill may cover one transfer and not a second. WETH could not pay those fees even if you had bridged the wrapper unchanged. Read the minimum POL before you assume the account is funded for a session.

Approval still costs Base ETH

The wrapper needs an allowance, and the allowance needs ETH on chain 8453. If ETH is zero, unwrap a slice of WETH first or add ETH. You cannot pay that Base fee with the POL you have not received. Declining the spender stops the route. The spender on Base is not a Polygon contract.

WETH on Polygon is the decoy

If the app address is 0x7ceB23fD6bC0adD59E62ac25578270cFf1b9f619, you want wrapped ether, not POL. If the app wants USDC or USDT, you want a dollar. If you only needed Base ETH, unwrap locally. WBTC is not this trade and is not native bitcoin. How cross-chain bridges work explains the handoff you do want when POL really is the target.

What a successful check looks like

Basescan: WETH balance down at the predeploy. Polygonscan: native POL up on the account. No token-transfer row is required for the arrival, because POL is not an ERC-20. Chain 137 must be the network in the wallet before that native line is the one you think it is. No fill time is promised.

Legal

Risk disclosure

XAUConnect is a non-custodial swap aggregator. Digital assets are volatile and may lose value rapidly. Content on this page is educational and not investment advice. Verify every contract address on the official block explorer before approving a transaction.

Frequently asked questions

What is the best way to swap WETH from Base to POL on Polygon?

You approve wrapped ETH at 0x4200000000000000000000000000000000000006 on Base, chain 8453. Basescan shows that ERC-20.

Is the POL I receive an ERC-20?

No. It is the native gas coin on chain 137. Quotes label it 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE, and Polygonscan shows the account balance. Polygon WETH, an ERC-20, is 0x7ceB23fD6bC0adD59E62ac25578270cFf1b9f619. If you needed that contract, this route is the wrong one. POL is only the gas coin, shown on the account in Polygonscan.

Can I unwrap Base WETH instead?

You can, and the result is ETH on Base, chain 8453, not POL on Polygon. Unwrapping burns 0x4200000000000000000000000000000000000006 locally. This page sends that wrapper toward chain 137 and credits POL. Use the unwrap only when you intend to stay on Base. This hop is for a POL balance on chain 137.

What pays for the approval?

ETH on Base. WETH is the token being approved, not the coin that pays gas, until you unwrap it. The POL you are buying is not on Base and cannot cover the fee. Keep a little ETH beside the WETH or the allowance cannot be mined.

Live execution

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Open the swap page with this cross-chain route pre-selected, then connect your wallet on the source chain to quote and execute. You keep the keys.

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