When is ETH Fusaka activation?

TLDR

Ethereum (ETH) Fusaka activates on 3 Dec at 21:49:11 (UTC) on mainnet (activation time).

1. Its a dual upgrade merging Osaka (execution) and Fulu (consensus) (overview).
2. Follow?on BPO capacity bumps are scheduled on 9 Dec and 7 Jan 2026 (schedule).
3. The trigger is expected to finalize within roughly 15 minutes (activation note).

Deep Dive

1. Activation Time

The mainnet activation window is precisely 21:49:11 (UTC) on 3 Dec at block slot 13,164,544 (activation details). CoinDesk notes the fork was triggered at 21:49 (UTC) and typically finalizes within about 15 minutes (finalization window).

2. What Fusaka Is

Fusaka combines the Osaka execution?layer upgrade with the Fulu consensus?layer upgrade, delivering scalability and efficiency improvements, anchored by PeerDAS (EIP?7594) for cheaper, higher?capacity L2 blobs (dual upgrade; roadmap context). PeerDAS lets nodes verify sampled slices of blob data rather than full blobs, reducing per?node load and enabling materially higher rollup throughput (mechanism).

3. Post?Activation Steps

Blob Parameter Only (BPO) forks raise blob targets incrementally after the main activation: BPO1 on 9 Dec 2025%%CKPROTECTED3%% and BPO2 on 7 Jan 2026%%CKPROTECTED5%%, further expanding data capacity for L2s (schedule). Ethereums official channels highlight the scalability focus and staged blob increases to safely ramp throughput (official thread).

Conclusion

Fusakas mainnet activation is set for 3 Dec at 21:49:11 (UTC), with quick finalization and staged capacity boosts shortly after. The dual upgrade (Osaka + Fulu) plus PeerDAS is designed to cut L2 data costs and expand throughput, so the most visible impact should emerge as L2s integrate changes over the next several weeks. For current context, see Ethereum (ETH) on the CoinsKid page.