Solana Activates 350-Millisecond Slots on Mainnet

Solana has activated a mainnet feature that cuts its target slot time from 400 milliseconds to 350 milliseconds, the network’s first slot-time reduction since its inception.

The change shortens the window for leaders to complete blocks and is intended to give users faster transaction confirmations. Solana’s explorer lists the SIMD-0525 feature as active on Mainnet Beta at slot 440,208,000 in epoch 1019.

For validators, the shift starts a staged transition rather than an immediate jump to the planned 200-millisecond endpoint. Each additional 50-millisecond reduction will activate through a separate feature gate in a later epoch, allowing the network to pause if block skip rates climb.

Jacob Creech, vice president of technology at the Solana Foundation, described the move Friday as Solana’s first slot-time reduction and said 300 milliseconds is the next target.

Four Feature Gates to 200 Milliseconds

Solana’s approved sequence moves from 400 milliseconds to 350, then 300, 250 and finally 200 milliseconds. The Solana Foundation says the network will not advance to the next reduction if block skip rates are too high.

Shorter slots compress the time for a leader to complete blocks, for the next leader to receive transactions through Gulf Stream, and for other validators to replay and vote on blocks. Solana said validator-client improvements, particularly in Turbine and Replay, enabled the plan.

The upgrade does not change the number of ticks per slot, the four-slot leader span or the number of slots in an epoch. Because those slots arrive more quickly, validators move through epochs in less elapsed time.

Solana labels the overall upgrade a breaking change and says required indexing changes remain to be determined. Its documentation still describes the default slot duration as 400 milliseconds, even though the explorer shows the first 350-millisecond feature as active.

Anza’s tentative Agave v4.2 schedule targets all four staged reductions for mainnet activation. The Solana upgrade page does not list a calendar date or specific epoch for the 300-millisecond step, and the network will not move to that reduction if block skip rates are too high.