Is Subnautica Below Zero multiplayer? No official co-op — but a full story-synced mod exists for Windows. Plus Nitrox and Subnautica 2's official co-op.
Subnautica Below Zero Multiplayer — Co-op Status, the Mod, and Subnautica 2
Subnautica: Below Zero has no official multiplayer — like the original game, it's single-player only, and Unknown Worlds never added co-op. On PC, however, a fan-made "Subnautica Below Zero Multiplayer" mod (full version, story-synchronized, Windows only) lets you play the entire campaign with a friend through a standalone launcher. Nitrox, the famous mod for the original Subnautica, does not support Below Zero. And if you want official co-op, that arrives with Subnautica 2, which launched Early Access on May 14, 2026 with up to 4-player multiplayer built in. This guide sorts out what's real, what's possible, and what to use.
Here's what you'll learn:
- The official multiplayer status (and why there isn't any)
- The Below Zero co-op mod: what it syncs, how it works, platform limits
- Why Nitrox doesn't cover Below Zero (and what it does cover)
- Console options and the Subnautica 2 official co-op
Official resources: Steam store page — Below Zero · Subnautica Below Zero Multiplayer mod · Mod source on GitHub · Nitrox for Subnautica
The Official Status: Single-Player Only
The short answer is no: Below Zero has no official multiplayer, on any platform, in any update. Unknown Worlds built both Subnautica games as single-player experiences — the co-op they originally experimented with during the first game's development was cut early and never made it into either release. Every official store page (Steam, Nintendo, PlayStation, Xbox) lists it as one player. That has never changed, and it's not coming via an update.
What has changed is the franchise's direction: Subnautica 2 ships with co-op as a headline feature — see the last section. For Below Zero itself, the only path to multiplayer is the fan mod below.
Per the official Subnautica Below Zero Multiplayer mod site: "This mod allows you to play Subnautica Below Zero in multiplayer with your friends… in the full version the whole story is synchronized and you can complete the story with your friend."
The Below Zero Co-op Mod (Windows PC)
The community answer is a standalone mod by ismail0234, distributed through subnauticamultiplayer.com and open-sourced on GitHub:
| What | Details |
|---|---|
| Current state | Full version, publicly available, story-synchronized |
| Platforms | Windows 8 / 8.1 / 10 / 11 only — Mac and Linux explicitly unsupported |
| Install | Standalone launcher (not a BepInEx plugin); download from the site, host or join via IP |
| Story sync | Full campaign completion together, including story events |
| What syncs | Bases (hull strength), vehicles (Seatruck, Snowfox, Prawn Suit, Spy Pengling), PDA logs, beacons, weather, items, world resources, oxygen plants, story flags |
The GitHub feature list is impressively long — vehicle movement sync, item pickup/drop sync, power management, base hull strength, PDA log and weather synchronization — which is why it's the only real option for BZ co-op. Practical notes from the community:
- The host's PC runs everything; the usual hosting-connection advice for modded co-op applies (port forwarding or VPN for joining over the internet).
- Both players need the same mod version and the same game version — check the site's download page before starting.
- Performance syncs to the host — a weak host PC means lag for the guest, not the host.
The mod's own site is explicit: "This version is not supported and will not be supported" for Mac and Linux. If you're on macOS or Linux, BZ co-op is not an option — and because it's a standalone launcher rather than a Nexus mod, follow the site's install steps exactly (our mods guide covers the BepInEx ecosystem, which is a separate path for single-player mods only).
Why Not Nitrox? (And What Nitrox Actually Covers)
Nitrox — the 3.3M+ download co-op mod — covers the original Subnautica only. It was built for the 2018 game's engine branch and does not support Below Zero. The two games are separate products with separate mod ecosystems (a fact our Subnautica mods guide covers in detail). So:
- Original Subnautica co-op: Nitrox (cross-store: Steam, Epic, Windows Store; up to ~100 slots, ~5 recommended).
- Below Zero co-op: the subnauticamultiplayer.com mod above.
- Both at once: not a thing — they're different games with different saves.
If you specifically want the original 4546B experience with a friend, use Nitrox — the Cyclops guide and the Below Zero map guide are both useful once you're in, co-op or not.
Console and Switch Options
No console version of Below Zero has mod access — the Switch, PS4/5 and Xbox ports are locked down, so co-op isn't possible on any of them, period. If you own Below Zero on console and want co-op, your options are: play it on PC (Steam/Epic), or wait for Subnautica 2 (below), which is the only entry in the series with console co-op plans.
Subnautica 2: Official Co-op Has Arrived
The franchise finally goes multiplayer with Subnautica 2, which entered Early Access on May 14, 2026 on PC (Steam, Epic, Microsoft Store) and Xbox Series X|S at $29.99:
- Up to 4-player online co-op from day one — the first official multiplayer in franchise history.
- Four pre-designed characters at launch, more customization through Early Access.
- Cross-platform play between Xbox and PC is in the design (Xbox Game Preview includes PC Game Pass crossplay).
- New planet (not 4546B), Unreal Engine 5, Early Access expected to run ~2–3 years before 1.0.
- Not on PlayStation or Switch at launch — console coverage is Xbox Series X|S only for now.
Per Microsoft's official Xbox Wire announcement: "For the first time in the Subnautica franchise, you can either traverse this mysterious new world alone or with up to three of your friends in optional co-operative multiplayer."
So the honest roadmap: want BZ co-op today → the fan mod (Windows). Want the full original game co-op → Nitrox. Want official, polished co-op → Subnautica 2 is live in Early Access right now, and it's covered in our games like Subnautica roundup.
FAQ
Does Subnautica Below Zero have multiplayer?
No official multiplayer — Below Zero is single-player only on every platform, and it never received co-op in an update. The only co-op option is a fan mod (PC/Windows).
Is there a co-op mod for Subnautica Below Zero?
Yes — the "Subnautica Below Zero Multiplayer" mod (subnauticamultiplayer.com, open-sourced on GitHub) is in full version with story synchronization. It's a standalone launcher for Windows 8/8.1/10/11; Mac and Linux are unsupported.
Does Nitrox work with Below Zero?
No — Nitrox only supports the original Subnautica (cross-store, 3.3M+ downloads). Below Zero is a separate game with a separate mod ecosystem; use the subnauticamultiplayer.com mod for BZ.
Can you play Below Zero multiplayer on console?
No. Console versions (Switch, PS4/5, Xbox) have no mod access, so co-op is impossible there. PC is the only platform with a Below Zero co-op option.
Will Subnautica 2 have multiplayer?
Yes — Subnautica 2 launched into Early Access on May 14, 2026 with up to 4-player co-op, the first official multiplayer in the franchise, on PC and Xbox Series X|S (not PlayStation or Switch at launch).
Related Guides
- Subnautica Mods Guide — Best Mods and How to Install
- Subnautica Below Zero Map — Biomes, Coordinates & Navigation
- Subnautica Spiral Plant — Location & Uses
- Games Like Subnautica — 15 Best Similar Games
Last updated: August 13, 2026.
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