BepInEx Setup Guide for Subnautica 2

BepInEx (BepIn Ex framework) is the most widely-used mod loader for Unity and Unreal Engine games. It lets C# plugins hook into the game at runtime. Most gameplay-changing mods for Subnautica 2 use it.

Prerequisites

• Subnautica 2 installed via Steam
• .NET 8.0 Runtime (for running C# mods)
• Windows 10/11 (Linux via Proton is supported but trickier)

Step 1 — Download BepInEx

Get the latest BepInEx build for Unreal Engine games from the official GitHub releases:

github.com/BepInEx/BepInEx/releases

Choose the BepInEx_win_x64 zip (even for Unreal titles).

⚠️ Do not use the Unity-specific build — Subnautica 2 is Unreal Engine 5.

Step 2 — Find Your Game Folder

In Steam:

1. Right-click Subnautica 2 → Manage → Browse local files.
2. You should see Subnautica2.exe (or the game's main executable) in this folder.

Typical path:

C:\Program Files (x86)\Steam\steamapps\common\Subnautica2\

Step 3 — Extract BepInEx

Extract the contents of the BepInEx zip directly into the game root folder — not into a subfolder. The result should look like:

Subnautica2\
├── BepInEx\          ← new folder from the zip
├── doorstop_config.ini  ← new file
├── winhttp.dll          ← new file (the patcher hook)
└── Subnautica2.exe   ← existing game executable

Step 4 — First Launch (generate config)

1. Launch Subnautica 2 via Steam as normal.
2. Let it reach the main menu, then quit.
3. BepInEx will have created:

   BepInEx\
   ├── config\     ← per-mod config files appear here
   ├── plugins\    ← drop mod DLLs here
   ├── patchers\   ← advanced patcher plugins
   └── LogOutput.log  ← your best friend when debugging
   

Step 5 — Install a Plugin Mod

1. Download a BepInEx mod (.zip containing a .dll).
2. Extract the .dll into BepInEx\plugins\.
3. Launch the game — the plugin loads automatically.

Some mods come with a named subfolder:

plugins\
└── AuthorName-ModName\
    ├── ModName.dll
    └── assets\   ← mod resources

Keep the folder structure as the author packaged it.

Verifying BepInEx Is Working

Open BepInEx\LogOutput.log in Notepad after launching. You should see:

[Message:   BepInEx] BepInEx 6.x.x - Subnautica2
[Info   :   BepInEx] Running under Unity ...
[Info   :   BepInEx] 1 plugins to load

If the log is empty or the file doesn't exist, the winhttp.dll hook isn't loading — check that you extracted to the correct folder.

Common Problems

Problem	Likely Cause	Fix
Log file empty	Wrong extract location	Re-extract to game root
Plugin not listed in log	DLL in wrong folder	Move to plugins\
Game crashes on load	Outdated mod	Check mod page for updates
"Missing dependency" error	Mod needs another mod	Install the dependency first

Video Reference

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Next: UE4SS Setup Guide →