Single-player games like Ostranauts
Below are 16 single-player Steam games similar to Ostranauts, 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 Ostranauts page.
Ranked picks
- 1
Hired Stars
Single-player alternative to Ostranauts — playable solo, no multiplayer required. Shares Indie with Ostranauts.
Lead a modular mercenary force in a sci-fi strategy sandbox. Plan your moves on a turn-based star map, then command your fleet in tactical, real-time isometric RTS battles. Plunder trade routes, hunt pirates, follow the story, upgrade modular ships, and level up captains to build the ultimate fleet.
- 2
Starship Simulator
Single-player alternative to Ostranauts — playable solo, no multiplayer required. Shares Simulation and RPG with Ostranauts.
Explore a scientifically accurate Milky Way galaxy and discover distant uncharted worlds, while having unrestricted access to every deck of your Magellan Class deep space exploration vessel. Interact with numerous fully simulated ship systems, or simply relax in the bar and watch the stars drift by.
- 3
Space Daram
Single-player alternative to Ostranauts — playable solo, no multiplayer required. Shares Indie and RPG with Ostranauts.
Become a cute space chipmunk and manage your ship with companions as you explore alien planets, build and upgrade your base, and craft gear by generating power and refining resources. Meet unique alien species, grow your foothold in the universe, and play solo or with friends in multiplayer.
- 4
Starminer
Single-player alternative to Ostranauts — playable solo, no multiplayer required. Shares Indie and Simulation with Ostranauts.
Design and build a massive interstellar fleet in this simulation sandbox. Strip space of its minerals for profit, but stay alert: your greed attracts the alien. Master deep base-building and deploy warships to protect your empire in immersive real-time space.
- 5
Starscrip
Single-player alternative to Ostranauts — playable solo, no multiplayer required. Shares Simulation and RPG with Ostranauts.
The top-down space sim. Fly, trade, and fight in a galaxy shaped by simulated history, where production, freight, and war reshape a living economy.
- 6
Starpoint Gemini 2
Single-player alternative to Ostranauts — playable solo, no multiplayer required. Shares Simulation and RPG with Ostranauts.
Captain your own space ship and roam the galaxy in 3D in this tactical space simulator with tons of RPG depth ! Space has never looked so inviting - but images can betray...It has been two years since the end of the second Gemini war, the situation in the wartorn system is further from resolution than ever.
- 7
Starpoint Gemini Warlords
Single-player alternative to Ostranauts — playable solo, no multiplayer required. Shares Simulation and RPG with Ostranauts.
Strategy from the front lines! Starpoint Gemini Warlords combines 3rd person capital spaceship combat with 4X strategy and RPG gameplay elements. Build mighty war fleets and send them into battle or lead them into combat yourself. Become the Warlord and conquer the Gemini system!
- 8
Evochron Mercenary
Single-player alternative to Ostranauts — playable solo, no multiplayer required. Shares Indie and Simulation with Ostranauts.
The life of an independent mercenary is rarely without excitement. Your spacecraft awaits and your adventure begins in the Sapphire star system.
- 9
NEO Scavenger
Single-player alternative to Ostranauts — playable solo, no multiplayer required. Shares Indie and RPG with Ostranauts.
NEO Scavenger is a game where you must survive in the wasteland long enough to figure out who you are. Each turn, you must decide where to go, how to scavenge for supplies, and how to deal with anything and anyone you encounter.
- 10
RimWorld
Single-player alternative to Ostranauts — playable solo, no multiplayer required. Shares Indie and Simulation with Ostranauts.
A sci-fi colony sim driven by an intelligent AI storyteller. Generates stories by simulating psychology, ecology, gunplay, melee combat, climate, biomes, diplomacy, interpersonal relationships, art, medicine, trade, and more.
- 11
The Expanse
Single-player alternative to Ostranauts — playable solo, no multiplayer required. Shares Early Access with Ostranauts.
You and your team are elite killers. Its your job to help defend and protect earth and inform us of your findings. The South East Spaceport have reported nightmareish zombies. The most unsettling thing is that people have changed and will not stop eating each other.
- 12
Project Zomboid
Single-player alternative to Ostranauts — playable solo, no multiplayer required. Shares Indie and Simulation with Ostranauts.
Project Zomboid is the ultimate in zombie survival. Alone or in MP: you loot, build, craft, fight, farm and fish in a struggle to survive. A hardcore RPG skillset, a vast map, massively customisable sandbox and a cute tutorial raccoon await the unwary. So how will you die? All it takes is a bite..
- 13
Firefly
Single-player alternative to Ostranauts — playable solo, no multiplayer required.
This is a relaxing and casual simulation game. Use tools such as countdown and focus alarm to improve your focus efficiency. Talk and interact with your partners to improve their favorability. The game scenes include classrooms, future cities, train compartments and ordinary houses.
- 14
Stationeers
Single-player alternative to Ostranauts — playable solo, no multiplayer required. Shares Indie and Simulation with Ostranauts.
Stationeers puts you in control of the construction and management of a space station to run by yourself or online with your friends. Complex atmospheric, electrical, manufacturing, agriculture, and gravitational systems require your thought and management at all times!
- 15
Kenshi
Single-player alternative to Ostranauts — playable solo, no multiplayer required. Shares Indie and Simulation with Ostranauts.
A free-roaming squad based RPG. Focusing on open-ended sandbox gameplay features rather than a linear story. Be a trader, a thief, a rebel, a warlord, an adventurer, a farmer, a slave, or just food for the cannibals. Train your men up from puny victims to master warriors.
- 16
Hardspace: Shipbreaker
Single-player alternative to Ostranauts — playable solo, no multiplayer required. Shares Simulation with Ostranauts.
Equipped with cutting-edge salvaging tech, carve & slice spaceships to recover valuable materials. Upgrade your gear to take on more lucrative contracts and pay your billion credits debt to LYNX Corp!