Nitrox Multiplayer for Subnautica on Linux

This guide helps you install the Nitrox multiplayer mod for Subnautica on Linux using Steam.

What is this?

• Nitrox lets you play Subnautica with friends
• You can explore the ocean together, build bases and survive as a team
• This guide makes installing Nitrox easy on Linux

What you need

• Linux (Ubuntu, Fedora, etc.)
• Steam
• Subnautica installed on Steam
• Internet connection

Usage

Clone the repository or download the files locally, in this directory :

1. Open config.sh and set your Steam folder path
2. In a terminal, run ./install.sh setup to:
   • Download and install Nitrox
   • Configure Steam launch options
   • Add NitroxLauncher to Steam
   • Store the Nitrox patch
3. Run ./install.sh patch to activate the mod
4. Launch Subnautica and play with friends!

[!NOTE] To patch and launch the game in one go (steps 3 and 4) : ./install.sh patch && steam steam://run/264710

For advanced users

You can do everything manually, the script is just a helper to guide you through the process and automate some steps.

Setup

1) Install Subnautica

Install Subnautica from Steam.

[!WARNING] Make sure to launch it at least once for the wine prefix to be created.

2) Install Nitrox

Download Nitrox from github : https://github.com/SubnauticaNitrox/Nitrox/releases/tag/1.7.1.0

The zip file is what we need.

Unzip the folder into your Subnautica prefix, at the root of the C: drive : $STEAM_DIR/steamapps/compatdata/264710/pfx/drive_c/Nitrox

264710 is the Subnautica Game ID on Steam.

3) Configure Subnautica on Steam

• open your Steam library
• right click on Subnautica in your library
• click on Properties
• in Set Launch Options, type -nitrox C:\Nitrox
• open the Betas tab
• on the dropdown, select legacy - Public legacy builds

4) Add NitroxLauncher to Steam

Add to Steam:

• open your Steam library
• click on Add a game on the bottom left corner
• select Add a non-steam game
• click on Browse... on the bottom left corner
• select NitroxLauncher.exe ; should be in $STEAM_DIR/steamapps/compatdata/264710/pfx/drive_c/Nitrox

NitroxLauncher should be added to your library.

Configure NitroxLauncher:

• right click on NitroxLauncher in your library
• click on Properties
• open the Compatibility tab
• enable Force the use of specific Steam Play compatibility tool
• on the dropdown menu, select Proton 8.0 or the latest version
• close the settings window

You should be able to launch NitroxLauncher from Steam. It can take a while to start, please be patient.

5) Copy the patch

When NitroxLauncher launches the game, it will patch the file Assembly-CSharp.dll in the game folder. The location of the file is $STEAM_DIR/steamapps/common/Subnautica/Subnautica_Data/Managed/Assembly-CSharp.dll

[!NOTE] When Nitrox exits, it will restore the patched file. We need to copy it from the game folder while Nitrox is running. Right now when we launch the NitroxLauncher from steam, Subnautica does not launch, but the patch is still applied.

We need to :

• launch NitroxLauncher from Steam
• click on the 'PLAY MULTIPLAYER' button
• a small blue popup should show up at the bottom with 'Launching Subnautica...'
• copy the patched file somewhere else
• close NitroxLauncher

We are good to go!

Launch Nitrox server

To launch the Nitrox server :

• open NitroxLauncher from Steam
• go to the 'SERVER' tab
• click on the 'START SERVER' button

Launch Subnautica with Nitrox

To launch Subnautica with Nitrox :

• replace the file Assembly-CSharp.dll in the game folder with the patched file you copied earlier
• launch Subnautica from Steam

The patch stays applied, but can be overriden by Steam (updates, etc).