Single-player games like I Thalassa
Below are 8 single-player Steam games similar to I Thalassa, ranked by player overlap. Every pick carries Steam's Single-player category, so multiplayer-only titles or always-online games don't sneak in. imho.run pulls the category data from Steam directly — Single-player here matches what the store labels.
Want the full alternatives list (paid + free + Steam Deck + cheaper picks)? See the parent games like I Thalassa page.
Ranked picks
- 1
Sonorous | Deep Down Below
Single-player alternative to I Thalassa — playable solo, no multiplayer required. Shares Adventure with I Thalassa.
SONOROUS – Deep Down Below is an unforgiving underwater first-person survival game set in a dystopian world. Find your sunken research to save humanity from an eternal life on the open sea in a continuous fight for survival.
- 2
Under A New Sun
Single-player alternative to I Thalassa — playable solo, no multiplayer required. Shares Adventure with I Thalassa.
While searching for a new home, an unexpected failure in your ship has left you stranded on a planet surprisingly similar to Earth. Discover a vast open world, hunt for food, develop technologies, and build yourself a new home to survive!
- 3
Submarine VR
Single-player alternative to I Thalassa — playable solo, no multiplayer required. Shares Adventure with I Thalassa.
Submarine VR takes you on a adventure-filled underwater simulation experience! Dive deep and cruise through the endless uncharted nature of the ocean and you will see clownfish, dolphins, penguins and mysterious sea animals. Get close to the sea surface and sail in the open sea with your cruise ship
- 4
subROV : Underwater Discoveries
Single-player alternative to I Thalassa — playable solo, no multiplayer required.
Pilot a remotely operated submarine and explore the oceans! Defy the darkness and crushing pressure of the deeps as you chart unknown regions and study new species of ocean life.
- 5
Under a Rock
Single-player alternative to I Thalassa — playable solo, no multiplayer required. Shares Adventure with I Thalassa.
A procedural open-world survival craft game for 1-10 players. Explore a primitive but dangerous place with a different evolutionary path; here, wildlife is oversized, Neanderthals still exist, and curses are real.
- 6
Darkwater
Single-player alternative to I Thalassa — playable solo, no multiplayer required. Shares Adventure with I Thalassa.
Darkwater is a cooperative extraction horror game for 1-4 players. Command a submarine trapped under the ice of an alien planet. Battle enemy vessels and deep sea abominations as you hunt for resources. Do what it takes to survive.
- 7
cyubeVR
Single-player alternative to I Thalassa — playable solo, no multiplayer required. Shares Adventure with I Thalassa.
Immerse yourself in a voxel game exclusively designed for VR. A beautiful infinite procedural world. Explore, gather resources, craft with your hands in 3D, and build anything you can imagine. Featuring great VR controls, near-infinite view distance, Steam Workshop mod support, and much more!
- 8
Maneater
Single-player alternative to I Thalassa — playable solo, no multiplayer required. Shares Adventure with I Thalassa.
Experience the ultimate power fantasy as the apex predator of the seas - a giant Shark! Terrorize the coastal waterways. Tear swimmers and divers limb from limb, give the humans a reason to fear you!