Subnautica: Below Zero

What Subnautica: Below Zero is

Below Zero is the standalone follow-up to Subnautica, released by Unknown Worlds in 2021. Same planet — 4546B — different pole. Instead of the temperate ocean you crashed into in the original, you arrive at an Antarctic ice shelf as Robin Ayou, a scientist investigating her sister's death at an Alterra research outpost. The world opens out across icebergs, frozen caves, glacial bays, and a wider above-water surface than the first game ever gave you, before sending you back into the deep.

Mechanically it's still Subnautica: scavenge materials, build a habitat, build vehicles, go deeper. What changed is the storytelling. Robin speaks — the silent-protagonist tradition of the original is dropped, with voiced dialogue, fleshed-out NPC interactions, and a much tighter narrative through-line. Where the original's story emerged from PDA logs you stumbled into, Below Zero hands it to you in cutscenes.

It's available on Steam, Epic, GOG, PlayStation, Xbox, and Switch. Mods, again, are a PC-only affair.

Modding: same toolchain, smaller catalogue

If you've modded the original Subnautica, you already know how to mod Below Zero. Same Unity engine, same .NET assemblies, same install pattern. The only thing that changes is which build of the bootstrapper you grab:

• BepInEx — bootstrapper. Use the Below Zero–specific build from the Nautilus team's releases, not the original Subnautica pack. The two games have different game DLLs and a mismatched BepInEx will refuse to load.
• Nautilus — the modding API. Same library as on the first game, with separate Below-Zero release artifacts. Most QoL-style mods exist for both games as parallel releases; some — especially ones touching biomes, vehicles, or story content — are Below-Zero-only.

The catalogue here is smaller than the original's — fewer years of community work, fewer authors. The floor is the same though: storage tweaks, vehicle balance, light controls, scanner improvements. If you want a step-by-step setup, the Getting Started with Subnautica Modding guide applies almost verbatim — just grab the Below-Zero packs instead of the original ones.

What's specific to Below Zero

A handful of categories matter more here because they're load-bearing for the Below Zero experience:

• Cold management & warmth — modders rebalance the original heating systems, add new insulation tiers, and tweak Robin's frostbite curves so the cold actually behaves like a survival mechanic rather than a UI annoyance.
• Above-water traversal — the first Subnautica barely needed snowfox-like vehicles, but the surface biomes here invite mods that expand snowfox utility, add new land vehicles, or improve fast-travel between surface and sea.
• Vehicle parity — the Cyclops is missing from Below Zero. Several mods bring back versions of it, expand the Sea Truck modular system to plug the gap, or rebalance the Prawn for the colder depths.

What's on OpenMods

Browse the full Below Zero catalogue from the Browse all Subnautica: Below Zero mods button on the right. The grid below is the most popular right now — typically a mix of cross-game ports (storage, lighting, QoL) and Below-Zero-native additions.