Not natively. Subnautica ships single-player; the community mod Nitrox adds co-op — Open-source co-op with over three million downloads; the ocean, bases and story sync well for a small crew.

Does Subnautica have PvP?

Only with the Nitrox mod, which is co-op only.

Do we both need to own Subnautica to play together?

Yes. Subnautica is played online, so each player needs their own copy on their own Steam account (or PC Game Pass where it is offered). Steam Families can share a library, but two people cannot play the same shared game at the same time.

How many people play Subnautica?

About 2,719 players were in-game when this page's data was last refreshed (2026-09-09).

Ready Up — what game do we play?Compare two Steam libraries →

Multiplayer games › Survival › Sci-fi survival

Is Subnautica multiplayer? Yes — with Nitrox

Not out of the box — but the Nitrox mod makes it co-op. Subnautica is a sci-fi survival game released in 2018, 97% positive on Steam (313,707 reviews), with 2,719 playing right now. $7.49 on Steam.

Co-opSingle-player tooMultiplayer via mod: NitroxSurvival · Sci-fi survival

How to play Subnautica with a friend: Nitrox

Open-source co-op with over three million downloads; the ocean, bases and story sync well for a small crew. Steam lists Subnautica as single-player, so it won't show up in Steam's own "games we both own" view as something you can play together — Ready Up counts it anyway, marked "Via mod", and you can hide mod-only games with one filter if that's not your thing.

Players: 2–100 (best with 5 or fewer)
Modes: co-op
Status: Maintained — works with the current game version and gets updates
You need: Nitrox launcher (Windows/Linux); one player hosts or runs a server
Price: Free

Get Nitrox All 77 games with multiplayer mods →

Descend into the depths of an alien underwater world filled with wonder and peril. Craft equipment, pilot submarines and out-smart wildlife to explore lush…

How Subnautica plays with friends, according to Steam

Online co-op: Not listed on Steam
Local / split-screen co-op: Not listed on Steam
Online PvP: Not listed on Steam
LAN play: Not listed on Steam
Single-player mode: Yes
Controller: Full controller support

Steam's own category list for the game, as of 2026-09-09. "Not listed" means the store page does not claim that mode; community mods or Remote Play can still add it.

Steam tags: Open World Survival Craft, Survival, Horror, Open World, Underwater, Exploration, Crafting, Base-Building

Do you and a friend both own Subnautica?

Ready Up compares two Steam libraries and shows every multiplayer game you both have — including whether Subnautica is one of them — then helps you pick tonight's game with a weighted roll or a bracket.

Or open the Steam store page.

Games like Subnautica you can play together

No Man's Sky

Sci-fi survival · 83% positive on Steam (352,858 reviews) · 12,291 playing right now

Space Engineers

Sci-fi survival · 89% positive on Steam (132,347 reviews) · 4,201 playing right now

Starbound

Sci-fi survival · 92% positive on Steam (164,906 reviews) · 894 playing right now

ASTRONEER

Sci-fi survival · 92% positive on Steam (128,956 reviews) · 988 playing right now

Subnautica: Below Zero

Sci-fi survival · 91% positive on Steam (96,660 reviews) · 698 playing right now

Cubic Odyssey

Sci-fi survival · 72% positive on Steam (1,509 reviews) · 429 playing right now

Tired of Subnautica? The Swap tab finds the closest unowned games of the same type that are newer or rated higher.

Quick answers

Is Subnautica co-op?: Not natively. Subnautica ships single-player; the community mod Nitrox adds co-op — Open-source co-op with over three million downloads; the ocean, bases and story sync well for a small crew.
Does Subnautica have PvP?: Only with the Nitrox mod, which is co-op only.
Do we both need to own Subnautica to play together?: Yes. Subnautica is played online, so each player needs their own copy on their own Steam account (or PC Game Pass where it is offered). Steam Families can share a library, but two people cannot play the same shared game at the same time.
How many people play Subnautica?: About 2,719 players were in-game when this page's data was last refreshed (2026-09-09).

Ready Up is a free tool: enter two Steam usernames and it lists the multiplayer games you both own, runs a bracket to pick one, and suggests new co-op games that fit how you both play. Ratings, tags and player counts from Steam and SteamSpy; page updated 2026-09-23. Powered by Steam — not affiliated with or endorsed by Valve Corporation or Microsoft. Ready Up is a Somebody Decide program. How the data works · Legal & privacy · All types · Game Pass