65%Strong matchThalassa: Edge of the Abyss
87%22987% positive reviews, Very Positive across 229 reviews·Interactive Fiction · First-Person
—Find a co-op game with friends
Descend into an alien ocean in this open-world survival adventure. Explore biomechanical depths, tame strange creatures, pilot submarines, and uncover the secrets of Thalassa – a mysterious entity watching from the abyss.
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I Thalassa
SteamAbout I Thalassa
The Ocean Remembers Everything
On a world far from Earth, a catastrophic incident transformed an alien ocean into something unprecedented — a realm where flesh meets metal, where creatures evolved into biomechanical hybrids, and where something ancient now stirs in the deepest trenches.
You are a survivor in this changed world. Explore, gather, craft, and build your way through an ocean that doesn't want you there. But you are not alone. Something watches from the abyss. Something that remembers.
Her name is Thalassa.
Key Features
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Explore an Alien OceanDive through vast underwater environments filled with hidden caves, ancient ruins, and biomechanical ecosystems unlike anything on Earth.
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Tame the UntameableThe creatures of this ocean are not merely animals. They are hybrids of organic life and machine. Learn to tame them, ride them, and survive alongside them.
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Pilot Submarines & VesselsDiscover and repair abandoned vehicles left behind by those who came before. Navigate the depths in submarines, ships, and experimental craft.
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Craft, Build, SurviveGather resources from the transformed seabed. Craft equipment. Build underwater bases. The ocean is hostile, but it also provides — if you know where to look.
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Uncover the MysteryWho was Dr. Mulane Shinoise? What did he create in his hidden laboratory? And what is Thalassa's true purpose? Follow the story or forge your own path — the choice is yours.
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Play Alone or Together Experience the depths in singleplayer or dive in with friends in cooperative multiplayer.
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Next-Gen VisualsPowered by Unity HDRP with realistic water simulation, volumetric lighting, and atmospheric effects that bring the alien ocean to life.
Early Access
I Thalassa is launching in Early Access. This means you'll be joining us on a journey — helping shape the game as we expand the world, add new creatures, vehicles, story content, and features based on community feedback.
Your discoveries will help build the future of Thalassa.
From the Depths
"The ocean keeps its secrets well. But secrets, like pressure, have a way of rising."
Descend into the unknown. Face the biomechanical creatures of the abyss. And perhaps, in time, you will learn what Thalassa truly wants.
Steam data © 2026 Valve Corporation. Trademarks are property of their respective owners.
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