L2 Gas Tracker
2026-09-11 · By L2 Gas Tracker Research

Optimism Gas Fees Explained: Is It Still a Top-3 Ethereum L2 in 2026?

Optimism gas fees explained showing how OP Mainnet Layer 2 transaction costs compare to Base and Arbitrum

The L2 people forget to mention

When someone says "Ethereum Layer 2," the conversation usually jumps straight to Base and Arbitrum. Optimism sits quietly in the background, which is odd because it's the chain that literally gave Base its tech — the OP Stack that Coinbase licensed to build Base on.

I've been using OP Mainnet alongside Base and Arbitrum for over a year now. The fees are comparable, the speed is comparable, and the DeFi ecosystem — while smaller than Arbitrum's — has real depth. The question isn't whether Optimism is good enough. It's whether it gives you something the other two don't.

Short answer: sometimes yes, mostly no, but the fee structure has one quirk that catches people off guard if they're used to Base.

How Optimism fees actually work

Same architecture as Base and Arbitrum: you pay an L2 execution fee plus an L1 data fee. The L2 execution fee is the cost of running your transaction on Optimism — fractions of a cent. The L1 data fee is your share of posting the batch to Ethereum mainnet, and it moves with mainnet congestion.

After the Dencun upgrade in 2024 introduced EIP-4844 blobs, Optimism's L1 data fee collapsed by roughly 90%, same as Base and Arbitrum. The blob market gives rollups a dedicated cheap lane for data posting, separate from regular mainnet gas. The result: fees that used to be $0.10 to $0.50 per swap dropped to $0.01 to $0.05.

One thing specific to Optimism: the chain uses a slightly different fee estimation than Base. If you check your wallet before signing, the estimated fee on OP Mainnet sometimes looks higher than what you actually pay. The execution fee gets refunded for unused gas — a small thing, but it means your wallet preview is a ceiling, not a precise quote.

Real costs on Optimism right now

Numbers I've seen consistently on OP Mainnet:

Side by side with Base, the fees are within 10% of each other on most transactions. Optimism is occasionally a touch cheaper on swaps; Base is occasionally cheaper on transfers. The difference has never changed a decision I've made about which chain to use.

The one area where Optimism clearly wins: smart contract wallet operations. Account abstraction on OP Mainnet — especially through Coinbase's Smart Wallet, which runs on the OP Stack — has the cheapest gas overhead for batched transactions I've seen on any L2.

When Optimism is the right pick

Honestly, for most users, Optimism vs Base vs Arbitrum comes down to where your money already is and which apps you use. But there are specific cases where OP Mainnet is the better call:

If you use a Coinbase Smart Wallet. The gas subsidization on OP Mainnet for smart wallet users is real — Coinbase covers gas costs up to a threshold, making transactions effectively free for casual users. That's a genuine edge no other L2 currently matches.

If you're into retroactive rewards. Optimism has run more retroactive airdrop seasons than any other L2. The chain rewards active users — bridge, swap, delegate, vote — and if you're positioning for future drops, OP Mainnet activity is the direct path.

If you're building on the OP Stack. Developers testing on the OP Stack testnet before deploying to Base or other OP chains will naturally use OP Mainnet for mainnet testing. Gas is the same architecture, so behavior is predictable.

The honest comparison

I use all three chains weekly. Here's the unvarnished version: Optimism is as cheap as Base, slightly less liquid than Arbitrum for DeFi, and its main differentiator is the Coinbase Smart Wallet integration and the retroactive rewards track record. The live tracker shows Base and Arbitrum fees in real time — Optimism sits in the same ballpark, so the dollar number isn't the deciding factor.

If you're already on Base or Arbitrum and happy, there's no urgent reason to move. If you're starting fresh and want the Coinbase on-ramp plus smart wallet benefits, OP Mainnet is worth a serious look. Pick by what you're doing, not by which chain has the louder marketing team.