Add Arbitrum One to MetaMask
The largest Ethereum optimistic rollup by TVL. Gas is paid in ETH.
Opens a MetaMask confirmation. Nothing is added until you approve it.
Network parameters
If you prefer to type them in by hand — MetaMask → network selector → Add a custom network. Checked 2026-09-14.
Arbitrum One https://arb1.arbitrum.io/rpc https://arbitrum-one-rpc.publicnode.com 42161 ETH https://arbiscan.io Adding it manually, step by step
- Unlock MetaMask and click the network name in the top-left corner.
- Choose Add a custom network (older versions: Settings → Networks → Add network → Add a network manually).
- Paste the six values from the box above into the matching fields.
- Press Save. MetaMask queries the RPC and checks that it really serves chain ID 42161.
- Select Arbitrum One from the network list. Your address stays the same — only the balances change.
If something goes wrong
“Chain ID returned by the network does not match”
The RPC URL points at a different chain than the ID you entered. Re-copy the RPC URL from this page; guides that were written years ago often list endpoints that have since been repurposed.
“Could not fetch chain ID” or an endless spinner
The public node is rate-limiting you or is temporarily down. Use the backup RPC URL above.
The network was added but my balance is zero
Balances are per-network. Holding ETH on an exchange or on another chain does not put it here — it has to be withdrawn or bridged to Arbitrum One specifically.