Nitrox mod

Nitrox is a community-developed multiplayer mod for the original Subnautica. It is the most popular mod in the franchise's history and arguably the single biggest demonstration of community demand for co-op multiplayer in Subnautica.

Features

Nitrox supports up to 100 players per server with native cross-play between Steam, Epic Games Store, and Microsoft Store versions. Players can explore, build bases, and survive together in the original Subnautica's world. The mod has its own Discord server with approximately 70,000 members.

Impact on Subnautica 2

The existence and popularity of Nitrox was a clear signal to Unknown Worlds that multiplayer was in demand. When Subnautica 2 was announced with official co-op support for up to 4 players, many in the community saw it as a natural evolution informed by Nitrox's success.

However, Nitrox's scale (100 players) versus Subnautica 2's cap (4 players) represents different design philosophies. Nitrox turned Subnautica into a shared server experience. Subnautica 2 treats co-op as a small-group addition to a fundamentally single-player game.

Modding ecosystem

The original Subnautica's modding scene uses BepInEx as the standard mod framework, with Nautilus (formerly SMLHelper) as the modding API. Mods are hosted on Thunderstore. Other popular mods include Map Mod (mini-map with fog-of-war), MoreQuickSlots, and Blueprint Tracker.

For Subnautica 2, the developers have stated there will be no modding support during Early Access. The shift from Unity to Unreal Engine 5 also means existing modding tools and frameworks from the original games won't be compatible.