Once Human heads to sea with enormous Isles of Abyss expansion

Once Human is leaving solid ground behind. Starry Studio has revealed Isles of Abyss, a free expansion arriving October 22 across mobile, PC, PlayStation 5 and Xbox Series systems. Billed as the game's largest update since its 2024 launch, Isles of Abyss adds five ocean regions and turns the sea itself into part of the threat. The water is connected to an ancient entity called the Sunken Lord, while islands, lighthouses and other seemingly useful landmarks may be considerably less friendly than they appear.

Players begin their nautical career with relatively modest skiffs but can eventually construct Mobile Sea Fortresses: floating bases equipped with workshops and heavy weaponry. Exploration does not stop at the waterline, either. Underwater areas contain resources and treasure that feed back into progression, giving players a reason to abandon the safety of their increasingly ridiculous battle-boats.

The expansion supports cross-play and cross-progression across its platforms, which is especially relevant to mobile players who want to continue the same survival run elsewhere. Once Human has always mixed survival mechanics with paranormal weirdness, but Isles of Abyss looks designed to change the actual geography of play rather than simply bolt another quest chain onto the existing world. The ocean is apparently alive, and naturally somebody decided the appropriate response was to build a fortress on it.