Cross-chain · Polygon → Base

Swap USDC from Polygon to WETH on Base

Swap USDC from Polygon to WETH on Base. Circle USDC leaves Polygon. WETH is what can arrive on Base. The wrapper uses the shared predeploy address and still cannot pay gas on chain id 8453.

Sell 0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359. Buy 0x4200000000000000000000000000000000000006. That address also exists as a predeploy on other OP Stack chains. On Base it is Base WETH, not Optimism's balance and not Ethereum WETH at 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2. Basescan is the credit. How cross-chain bridges work keeps those same-looking addresses apart.

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

Same address, wrong chain

Seeing 0x4200000000000000000000000000000000000006 on Optimism does not mean the tokens are on Base. Chain id 8453 is the only credit that counts. If your wallet is on another OP Stack chain, this route is wrong.

WETH will not pay Base

Native ETH does. If you needed gas, buy the 0xEeee label instead. ETH is not WETH. A wallet that receives only the wrapper can sit unable to unwrap it.

USDC.e again

Approving 0x2791Bca1f2de4661ED88A30C99A7a9449Aa84174 spends the bridged dollar, not this quote. Native USDC is 0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359. POL must remain on Polygon.

Not mainnet WETH

Etherscan and chain id 1 are the wrong record. Basescan shows the predeploy. About 12 second mainnet blocks are not this credit and not the bridge clock.

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 USDC from Polygon to WETH on Base?

Sell 0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359. Buy 0x4200000000000000000000000000000000000006. XAUConnect compares live routes and lets your own wallet sign.

Can I unwrap Base WETH with no ETH?

No. Moving 0x4200000000000000000000000000000000000006 costs ETH on chain id 8453. This route does not include that ETH. ETH is not WETH. Basescan can show the wrapper while the ETH line is empty. Fund ETH first if you must touch it. The same address on another chain is not this balance.

Is this Ethereum WETH?

No. Ethereum WETH is 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2. This credit is the Base predeploy. You sell Polygon USDC at 0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359. Etherscan will not show the debit or the credit. Basescan, chain id 8453, is the destination explorer. Mainnet WETH is a different contract on chain id 1. Do not paste it into Base.

Which Polygon USDC is valid?

Native Circle USDC only. USDC.e at 0x2791Bca1f2de4661ED88A30C99A7a9449Aa84174 is the wrong source. Polygonscan shows the approval. POL pays chain id 137. If the wallet approves the bridged contract, you are on the wrong route. Native USDC and USDC.e are different Polygon balances. Check the approval target on Polygonscan.

Live execution

Trade on XAUConnect

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.

Swap cross-chainExplore markets

Continue exploring

Related markets, guides & networks

Next pages on this subject. Read them before you trade.

Networks
Tokens
Guides
Articles

Build programmatically

Swap via API for bots and AI agents: quotes, builds, and cross-chain routes.

Developer quickstart