When is ETH Fusaka activating?

TLDR

Ethereums Fusaka upgrade is scheduled to activate on 3 Dec 2025 at 21:49 UTC at slot 13,164,544. See the exact time and slot in this report from CCN.

1. Follow-up blob capacity BPO forks are planned for 9 Dec 2025 and 7 Jan 2026, per CCN.
2. The headliner is PeerDAS, aiming to cut L2 data costs and raise throughput, explained by Cointelegraph.

Deep Dive

1. Activation Details

Fusakas mainnet activation is set for 3 Dec 2025 at 21:49 UTC, with the activation defined at slot 13,164,544. This timing and slot are outlined in a detailed guide by CCN.

Some coverage noted the timeline coalesced after testing across public testnets, which helps de-risk the rollout sequence ahead of mainnet go-live, according to crypto.news.

2. BPO Forks After Fusaka

Two Blob Parameter Only (BPO) forks are slated shortly after Fusaka. The first is expected on 9 Dec 2025 and the second on 7 Jan 2026, intended to incrementally raise blob throughput and refine data fee dynamics for rollups, per CCN.

Additional overviews highlight that the full rollout sequence uses these smaller parameter updates to scale capacity without one-time shocks, as summarized by Cointelegraph.

3. Why It Matters

Fusaka centers on PeerDAS (peer data availability sampling), which lets nodes verify rollup data without downloading it all, lowering per-node bandwidth and enabling substantially higher data throughput for L2s, explained by Cointelegraph.

Analyses suggest these changes should help reduce L2 data costs, improve fee predictability, and position Ethereum as a higher-capacity settlement and data layer for rollups, according to Cointelegraph.

Conclusion

Fusaka activates on 3 Dec 2025 at 21:49 UTC (slot 13,164,544), with staged BPO updates in December and January to scale blob capacity. The upgrades PeerDAS and parameter changes are designed to cut L2 data costs and raise throughput, supporting Ethereums role as a high-capacity settlement layer for rollups.