Once Human’s Isles of Abyss expansion is out now and free, Starry Studio announced on Thursday, October 22, 2026. The studio calls it “the largest free expansion in Once Human history,” a history that began on July 9, 2024, and on paper the claim holds. It is live on PC, PlayStation 5, Xbox Series X|S and mobile, and it moves the survival game off the land and onto the water.
Crews build and sail ships together in what the studio calls Fleet Co-Op, squads can mix platforms, and the final boss is a four-player co-op raid. The announcement says nothing about private or dedicated servers. Instead it treats each server as one team, with a shared progress bar everyone fills together.
How a ship turns into the base
A new ocean tech tree runs alongside the land one. You start with canvas sails and work up to fuel and electric propellers, then mount tiered cannons and harpoon turrets. The deck takes automated fishing nets, smelters, generators and workbenches, so the ship becomes “a self-sustaining mobile fortress,” in Starry Studio’s words. That is a factory with a keel, and it is the part of this expansion I would read twice. Once Human started on dry land, and now the base can leave it.
The sea is split into five zones. After a starting area of plains, you sail into four marine sectors, and each one turns its hazard into its resource. Mist of Deceit steals your vision, Schwarze Flut drains sanity, Time Rain corrodes gear but speeds up crops, and Skyfire drops volcanic meteor storms. You harvest the hazard to craft the tech that survives it. Each region is guarded by a Tower of Calamity, a huge lighthouse with tentacles. Crews take it down with naval cannons and firearms to unlock the next crafting tier and the next region. Five ghost ships also roam the mist, and boarding one pays out in rare blueprints and modules.
And then it gets complicated, on purpose. Isles of Abyss runs on a 21-day cycle in two phases. The faster a server clears the five regions and their towers in Phase 1, the sooner Phase 2 starts, with random Corruption Zones and bosses like the Doom Owl. Every purged anomaly feeds the server’s progress bar, and a full bar wakes The Sunken Lord. That is the raid where squads of four fight through the leviathan’s insides to its heart.
For a crew that plays twice a week, that clock cuts both ways. The nightly players on your server will drag Phase 2 forward whether your group is ready or not, so the ship had better be armed before the bar fills. There is also a limited-time Halloween Meets the Abyss festival, and a Deviant called Duet that you can capture to change the weather and the wind.
It is free on Steam and every other platform now. Pick a server the whole crew agrees on before anyone lays a hull, because on this one the clock belongs to everybody.
