Once Human has taken its survival formula offshore. The free Isles of Abyss expansion brings buildable ships, underwater exploration and a new PvE endgame to Xbox Series X|S — alongside a separate, riskier PvP mode.
In Once Human, choosing where to build a base has always mattered. Isles of Abyss makes that decision a little more adventurous: your next home can be a ship, with supplies, equipment and weapons travelling alongside you as you cross an unfamiliar ocean.
Starry Studio’s biggest free expansion is now live on Xbox Series X|S, following the 21 October update in Pacific Time — 22 October 2026 in the UK. Announced at September’s Xbox Tokyo Game Show broadcast, it opens an archipelago of wrecks, hostile ships and something unsettling beneath the water.
Ship upgrades feed into new progression rules, co-operative challenges and a confrontation with the Sunken Lord.
Is Isles of Abyss free, and do Xbox players need Game Pass?
Isles of Abyss is a free update to the free-to-play Once Human. You do not need to buy the expansion or take out Game Pass solely to access the game. The Xbox Series X|S version launched in August, so this is new content for an existing console release, not a separate Xbox debut.
Xbox’s announcement says “included with Game Pass”, but the game remains free-to-play. Xbox also advertises membership benefits for subscribers. The update is also available on PlayStation 5, PC and mobile; the wider game supports cross-play and cross-progression.
For returning players, the route in is through the updated game and its scenario-selection screen. Starry Studio’s 21 October release notes list an approximately 20.39GB Xbox launcher download, plus a much smaller in-game update. Actual downloads may differ, so it is sensible to check storage space before setting sail.
Build a ship instead of returning to a fixed base
Ship-building sits at the heart of the update. Open Build Mode and you can assemble a vessel from hull, deck and other structural pieces, fit out working spaces and save the result as a Design Layout. Friends can share layouts rather than rebuilding each ship from scratch.
A ship can be placed on the water using relocation or the vehicle-summoning command. Sailing is not the only means of movement: the developer describes propulsion options that expand with progression, including fuel and electric power. Auto Cruise offers route planning, while onboard facilities and return options are intended to make longer expeditions practical.
It is also a fighting platform. Harpoon cannons, naval guns, ramming equipment and mines give crews ways to defend themselves. Enemy Voyager vessels can be disabled, boarded and looted, and their fleets grow more formidable as the scenario develops.
It sounds more flexible than constantly returning to a land base, although Tech Torque Media has not tested ship construction or handling with an Xbox controller.
Five regions above and below the waves
The new ocean stretches across five distinct regions, with islands to search, resources to gather and dangerous waters between them. An expedition might begin with beachcombing or a message in a drifting bottle and end with a dive towards a wreck, submerged structure or treasure cache.
Underwater trips bring their own kit requirements. Oxygen supplies and diving equipment matter, while sharks, giant squid and other creatures make the journey less predictable. Resources collected from the coast and seabed can feed into crafting, equipment and ship upgrades. Choosing what to carry and when to head back matters.
The ocean itself is tied to the Sunken Lord, a monstrous presence woven into the expansion’s story. Ghostly vessels and violent weather make the sea feel inhospitable even between encounters.
Progression has changed — even for experienced players
Isles of Abyss is a PvE scenario, with an intended main cycle of roughly 21 days rather than an open-ended campaign. Its first phase lasts around five to ten days, depending on server purification progress; the second runs for 11 days and brings harder challenges. Those are server phases, not a completion-time estimate for individual players.
Veterans should pay particular attention to the new Tech progression. Characters enter at maximum level, but higher-rarity crafting and active Mod attributes unlock as Tech advances. Existing blueprints and Mods can be brought in; they will not necessarily perform as they did in a mature previous scenario. The familiar Cradle system is unavailable here.
Basic supplies help establish a ship; tougher encounters offer materials for better gear. Returning players will need to watch their Tech unlocks, not just their old loadouts.
What awaits at the endgame?
The Calamity Tower develops from earlier challenges into demanding naval fights, with tentacles, weak points and hazards that make positioning important. Later phases bring bigger Voyager fleets and a Sea Calamity Zone with mines, turrets and shielded targets.
The Sunken Lord encounter opens once the server reaches the relevant purification milestone. Players then face a sequence of encounters before reaching the boss’s core. Heart of the Ocean, an advanced scenario resource earned through exploration and challenges, is used to claim certain higher-level rewards.
Whether those battles scale well for small groups, or reward repeated runs, remains to be seen.
RaidZone is a different proposition
Isles of Abyss: RaidZone is the accompanying PvP experience, not the default ruleset for the main ocean-survival scenario. Rival crews compete for scarcer resources and can attack each other’s ships. If your ship sinks in RaidZone, supplies stored aboard are not refunded. A saved blueprint helps rebuild the vessel, but not recover everything it carried.
There is also a server distinction worth checking before joining friends. A server marked [Console] is restricted to console players, despite the cross-play features available elsewhere. Anyone after the co-operative PvE adventure should select that scenario rather than assuming every Isles of Abyss server works the same way.
How to join — and a launch reward worth checking
New players must finish character creation and the introductory experience before selecting Isles of Abyss. Existing characters can use scenario sign-up under the normal transfer rules. European servers were included in the launch allocation, although available places will depend on the live server list.
It is worth checking the in-game mailbox, too. The official update notice advertises a launch celebration supply package claimable from in-game mail until 8 November, 2pm Pacific Time, including weapon and gear blueprints and Starchrom. Check the current in-game eligibility and deadline rather than assuming rewards arrive automatically.
The official Isles of Abyss release trailer shows the ships and ocean threats, although not how well they perform on Xbox.
Tech Torque Verdict
A base that can sail away changes the decisions players make in a survival game. Ship layouts, supplies and weapons all become part of the same voyage, while the split between PvE and RaidZone lets players choose how much risk they want from other crews.
There are still questions: controller-friendly construction, the pace of Tech unlocks, solo-player options and whether repeated trips stay interesting. We have not played this expansion, so this is an assessment of the confirmed features, not a review. As a free update for Xbox survival fans, though, Isles of Abyss offers plenty of reasons to give the ocean a try.
