How to Add Arbitrum Sepolia to MetaMask (Step-by-Step)

Arbitrum Sepolia is Arbitrum’s public test network. Use it to test apps, contracts, and workflows without risking real funds.

What is Arbitrum Sepolia?

Arbitrum Sepolia is the testnet version of Arbitrum One, the popular Ethereum Layer-2 (L2) rollup. It mirrors mainnet features at low cost so builders can deploy and iterate quickly.
If you’re experimenting with dapps, contracts, or bridging flows, adding Arbitrum Sepolia to MetaMask lets you sign and send test transactions using free test ETH.

Network type: Ethereum L2 (testnet)
Gas token: ETH (testnet)
Use cases: Contract testing, front-end integration, wallet and UX testing, education
Do not use for real value: Testnet ETH has no monetary value.

Arbitrum Sepolia — Network Settings (Copy & Paste)

When adding the network manually in MetaMask, use these exact values:

Network Name: Arbitrum Sepolia
New RPC URL: https://sepolia-rollup.arbitrum.io/rpc
Chain ID: 421614
Currency Symbol: ETH
Block Explorer URL: https://sepolia.arbiscan.io

Tip: if MetaMask reports “Invalid chain ID” or “could not fetch chain ID”, double-check the Chain ID (it’s 421614) and the RPC URL spelling.

Add Arbitrum Sepolia to MetaMask (Desktop)

Open MetaMask in your browser and unlock your wallet.
Click your account avatar > Settings > Networks > Add a network.
Choose Add a network manually.
Paste the values from the block above into the MetaMask form:
- Network Name — Arbitrum Sepolia
- New RPC URL — https://sepolia-rollup.arbitrum.io/rpc
- Chain ID — 421614
- Currency Symbol — ETH
- Block Explorer URL — https://sepolia.arbiscan.io
Click Save. MetaMask will switch to Arbitrum Sepolia.

You should now see “Arbitrum Sepolia” in the network picker at the top of MetaMask. If you don’t, repeat the steps and confirm there are no extra spaces in the RPC URL or Chain ID.

Add Arbitrum Sepolia to MetaMask (Mobile)

Open the MetaMask app and unlock.
Tap the network selector at the top (e.g., “Ethereum main network”).
Tap Add network > Custom networks.
Enter the same values shown above and tap Add, then Switch to Arbitrum Sepolia.

Get Test ETH on Arbitrum Sepolia

To send transactions (deploy contracts, interact with dapps), you need a small amount of test ETH on Arbitrum Sepolia.
There are two common paths:

Direct L2 test-ETH faucets: Several reputable providers periodically offer Arbitrum Sepolia test ETH. Requirements vary (e.g., GitHub or X account). If one faucet is rate-limited, try another. Try quicknode Faucets
Bridge from Ethereum Sepolia: You can first acquire ETH on the Ethereum Sepolia L1 testnet from an Ethereum faucet, then use an Arbitrum testnet bridge to move funds to Arbitrum Sepolia. Expect a short delay while the bridge finalizes.

Important: Testnet ETH is strictly for development; it cannot be swapped for real assets.

Quick Sanity Checks

Network name shows “Arbitrum Sepolia” in your MetaMask network picker.
Your account address looks the same as on Ethereum (same keys), but your balance on Arbitrum Sepolia will be different.
The block explorer for this network is sepolia.arbiscan.io. Paste your address there to see testnet transactions.

Troubleshooting (Read This If Something Fails)

“Couldn’t fetch chain ID” or the form won’t save

Usually a typo or an extra space in the RPC URL. Copy the RPC and Chain ID again, exactly. If your browser has strict privacy extensions, temporarily allow the RPC domain.

Stuck pending / no response from RPC

Public RPCs can be rate-limited. Wait a minute and try again, or switch to another provider’s RPC (many infra providers offer free testnet endpoints). Also make sure your wallet is actually on Arbitrum Sepolia, not Ethereum Sepolia.

Explorer shows “No transactions found”

Confirm the explorer URL is the Arbitrum Sepolia one (https://sepolia.arbiscan.io) and that your MetaMask is on the same network. If you just sent a TX, give it 10–30 seconds and refresh.

Contracts compile but deployments fail

Ensure your toolchain is pointing to the Arbitrum Sepolia RPC and chain ID. Many frameworks (Hardhat, Foundry, Truffle) cache networks—restart your dev server after changing RPCs.

FAQs

Is Arbitrum Sepolia the same as Ethereum Sepolia?

No. Ethereum Sepolia is the L1 Ethereum testnet. Arbitrum Sepolia is an L2 rollup testnet that settles to Ethereum Sepolia. They’re separate networks with different RPCs, explorers, and balances.

What token pays gas on Arbitrum Sepolia?

ETH (testnet). You can’t use real ETH here, and tokens have no market value.

Can I bridge tokens from Ethereum Sepolia to Arbitrum Sepolia?

Yes, use a testnet bridge that supports Arbitrum Sepolia. You’ll deposit from Ethereum Sepolia and receive test tokens on Arbitrum Sepolia after finality. Always verify the bridge domain and read limits or rate caps.

How do I remove the network later?

MetaMask > Settings > Networks > select Arbitrum Sepolia > Delete. You can re-add it any time with the values above.

Copy Block (for your team docs)

Share this with teammates to eliminate copy errors:

{
  "chainName": "Arbitrum Sepolia",
  "chainId": 421614,
  "nativeCurrency": { "name": "Sepolia ETH", "symbol": "ETH", "decimals": 18 },
  "rpcUrls": ["https://sepolia-rollup.arbitrum.io/rpc"],
  "blockExplorerUrls": ["https://sepolia.arbiscan.io"]
}

Some tools support JSON-style network configs; if yours doesn’t, just use the earlier plain-text block.