To bridge assets: choose a bridge (official rollup bridge for max security, or Across/Stargate for speed), connect your wallet, select source and destination chains, pick the token and amount, approve the transaction, and wait for confirmation on the destination. Costs range from $0.50 to $15 depending on the bridge and chains involved. Always use the correct bridge for your security needs.
How to Bridge Assets Between Chains
4 min read
The short version
Bridging moves your crypto from one blockchain to another. Your ETH on Ethereum mainnet cannot magically appear on Arbitrum without a bridge because they are separate networks. The bridge locks your tokens on one side and releases equivalent tokens on the other. Choosing the right bridge is the single most important decision because bridges are the most-attacked infrastructure in crypto.
How It Works
Three bridge categories ranked by security. Official rollup bridges (highest security, slowest): Arbitrum bridge (bridge.arbitrum.io), Optimism bridge (app.optimism.io/bridge), zkSync bridge (bridge.zksync.io). These are part of the rollup protocol itself. Security backed by Ethereum L1. Deposits: 10-15 minutes. Withdrawals: 7 days for optimistic rollups, hours for ZK rollups. Best for: large amounts where security matters more than speed. Third-party liquidity bridges (good security, fast): Across Protocol (across.to), Stargate (stargate.finance), Chainlink CCIP. These use their own validator sets or liquidity networks. Transfers complete in 2-10 minutes in either direction. Fees: 0.05-0.5% of transfer amount. Best for: daily use, moderate amounts, speed-sensitive transfers. Aggregators (convenience, variable security): Bungee (bungee.exchange), LI.FI, Socket. These find the cheapest/fastest route across multiple bridges. Good for price comparison but you inherit the security of whichever underlying bridge they route through. The bridging flow: (1) Connect wallet to bridge UI. (2) Select source chain (where tokens are now). (3) Select destination chain (where you want them). (4) Choose token and amount. (5) Approve token spending if needed (first time only per token). (6) Confirm the bridge transaction. (7) Wait for destination confirmation. (8) Tokens appear in your wallet on the new chain.
Bridging 2,000 USDC from Ethereum to Arbitrum via Across
You have 2,000 USDC on Ethereum mainnet and want it on Arbitrum for cheaper DeFi. Using Across Protocol: (1) Go to across.to, connect MetaMask (on Ethereum network). (2) Set From: Ethereum, To: Arbitrum, Token: USDC, Amount: 2000. (3) Across quotes: ~1,997 USDC received on Arbitrum (fee: ~$3 / 0.15%), estimated time: 2-5 minutes. (4) Click Send, approve USDC spending (first time: one extra transaction, $3 gas). (5) Confirm the bridge transaction ($5-10 gas on L1). (6) Wait approximately 3 minutes. (7) Switch MetaMask to Arbitrum network. 1,997 USDC appears in your balance. Total cost: ~$8-13 (L1 gas) + $3 bridge fee = $11-16 total. Time: 3 minutes. Compare to official Arbitrum bridge: same $8-13 gas, but 10-minute deposit wait (faster in this direction, but 7 days for withdrawals back to L1).
What People Get Wrong
All bridges are equally safe
Bridge security varies enormously. Official rollup bridges inherit Ethereum L1 security (900K+ validators). Third-party bridges rely on their own validator sets (sometimes 5-20 validators). Over $2.5 billion has been stolen from bridges since 2021. Check L2Beat for bridge risk assessments before using any bridge with large amounts.
Bridging is the same as sending tokens
Bridging involves locking on one chain and minting/releasing on another. It is a more complex operation with more points of failure than a simple transfer. Failed bridges can leave tokens stuck (locked on source but not released on destination). Always verify completion on both chains.
You need to bridge back through the same bridge you used
No. If you bridged ETH to Arbitrum via the official bridge, you can bridge it back using Across, Stargate, or any other bridge. The tokens on the destination chain are standard tokens regardless of how they arrived. Use whichever bridge offers the best speed/cost for your return trip.
Keep Reading
Sources & Further Reading
- Across Protocol
Fast intent-based bridge with competitive fees (2-5 min transfers)
- Arbitrum Bridge
Official Arbitrum bridge backed by Ethereum L1 security
- L2Beat Bridges
Risk assessment and comparison of all major bridges
Questions People Also Ask
- What if my bridge transaction gets stuck?
- For official rollup bridges: transactions cannot truly get stuck (they either complete or can be force-included via L1). For third-party bridges: check the bridge UI for a claim button on the destination chain (some require manual claiming). If stuck longer than expected: contact bridge support on their Discord with your transaction hash. Funds in official bridges are never lost (worst case: delayed).
- Is it cheaper to bridge or to withdraw to CEX and redeposit?
- For Ethereum to L2: bridging is almost always cheaper and faster ($5-15 bridge vs $5 withdrawal + $5 deposit + exchange spreads + waiting time). For between unrelated L1s (Ethereum to Solana): often comparable. For very large amounts ($100K+): CEX route may offer better execution due to avoiding bridge price impact.
- Can I bridge any token between any chains?
- Not always. Bridges support specific token/chain combinations. Major tokens (ETH, USDC, USDT, WBTC) are supported on most bridges. Smaller tokens may only be available on specific bridges or may need to be swapped to a bridgeable token first, then swapped back on the destination chain.