How to install Subnautica 2 mods, and how to make your first one

Subnautica 2 entered Early Access on 14 May 2026, and it has no official mod support. Modding runs on community tools built for Unreal Engine 5, which makes it a completely different process from the original Subnautica's BepInEx and Nautilus. If you're here for the first game, the Subnautica modding guide is the one you want.

The first half of this guide is for players installing mods. The second half is for anyone who wants to make one.

Installing mods

Start with UE4SS

Most gameplay mods need UE4SS, an Unreal Engine scripting system that lets mods run code inside the game. The Subnautica 2 community maintains its own build: download it from the Subnautica2-UE4SS releases page or its Nexus page.

The release offers two zips. The plain UE4SS_…zip is for players. The zDEV- version adds developer tools you only need when making mods.

Extract it into the game's Win64 folder, so that dwmapi.dll and the ue4ss folder sit directly inside it:

steamapps\common\Subnautica2\Subnautica2\Binaries\Win64\

There's also an Engine folder in the install. It's the wrong one, and UE4SS won't load from there.

Launch the game once. If a UE4SS.log file appears inside the ue4ss folder, it's working.

Where each type of mod goes

Unreal mods don't all install to one place, which is the most common reason a mod "does nothing".

Mod type	What it contains	Where it goes
UE4SS script mods	A folder of Lua scripts	Binaries\Win64\ue4ss\Mods\
Blueprint mods	.pak, .ucas and .utoc files in a named folder	Subnautica2\Content\Paks\LogicMods\
Asset replacement paks	.pak files that swap textures, models or data	Subnautica2\Content\Paks\~mods\

Create LogicMods or ~mods yourself if they don't exist yet. Each mod's page should say which type it is and what it requires. When a page gives specific install steps, follow them instead of the table.

Where to find mods

Subnautica 2 mods are published on Nexus Mods and on CurseForge, which can also install them through its own app. OpenMods lists Subnautica 2 mods that are developed in public on GitHub, with links to each one's source code and releases.

Co-op and saves during Early Access

Two rules keep a modded session from going wrong:

• Everyone in a co-op session needs the same mods. Mismatched mod lists desync the world, and a host's mods can damage a guest's progress.
• Back up your saves before installing anything that touches them. That includes inventory, bases, custom items and new creatures. The save format will change during Early Access, and mods that edit save data break when it does.

After a game update, expect some mods to stop working until their authors catch up. To turn every UE4SS mod off at once, rename dwmapi.dll in the Win64 folder. Rename it back to turn them on again.

Making your first mod

The community's starting point is the Subnautica2-Project template, maintained by the Subnautica2Modding group. It's also listed on OpenMods as mod 61. What follows summarises its README. When the two disagree, the README is the authority, because the project moves fast.

What to install

• A custom build of Unreal Engine 5.6, linked from the template's README. It's required, because the stock engine can't open or reference all of the game's content, or add custom materials and items. It's also about 10 GB smaller than the Epic Games Launcher version, and there's nothing to compile. The download link only works after you link your Epic Games and GitHub accounts; otherwise GitHub shows a 404. Install it near the root of an SSD, on a path with no spaces. Long or unquoted paths break things.
• Visual Studio 2022 with the MSVC v14.38 toolchain. Newer toolchains refuse to open the project with a "detected compiler newer than Visual Studio 2022" error. Find v14.38 under Individual components in the Visual Studio Installer.
• FMOD for Unreal, the audio plugin, from fmod.com. It needs a free account, and it can't ship in the template because its files are licensed.

Setting up the project

Clone or download the template, then run two scripts from its folder:

powershell -ExecutionPolicy Bypass -File setup-fmod.ps1 -FMODPluginZip "C:\path\to\fmodstudio20309ue5.6win64.zip"
.\copy-fmod-banks.ps1

The first extracts FMOD's DLLs from the zip you downloaded. The second copies the game's audio banks from your Subnautica 2 install. Re-run copy-fmod-banks.ps1 every time the game updates.

Open Subnautica2.uproject. The first launch compiles shaders and can sit apparently frozen for several minutes. Leave it alone until it finishes.

Creating and installing a mod with Mod Tools

The template includes the SN2 Mod Tools editor plugin, mainly developed by bmartin127, which automates the tedious parts. Find its button in the play-in-editor toolbar.

1. Open Plugin settings… and check that the game install path is right.
2. Click New mod… and name your mod. It creates the mod folder, a ModActor blueprint that UE4SS loads automatically, and a Primary Asset Label with an unused chunk ID already assigned.
3. Build your logic in the ModActor's event graph. A good first mod is changing one value on a game data asset, such as one of the DA_ assets.
4. Right-click the mod folder and choose Cook & Install. The plugin cooks the project, packages your mod and installs it into the game.
5. Use Launch Subnautica 2 from the Mod Tools menu to test. This only works with the Steam version.

Install and Uninstall are on the same right-click menu, so you can reinstall several mods after a single cook.

The rules the tools enforce for you

If you ever package by hand, which the README also documents, three rules matter. Every mod needs its own chunk ID between 1 and 300. Never use 0, which holds the base project content. And the installed .pak, .ucas and .utoc files must be renamed to match the mod's folder name exactly, or the mod silently fails to load.

For general Unreal modding technique, the README recommends Dmgvol's UE Modding guides, particularly the intermediate sections and above.

Credit for the template, the FMOD scripts and the packaging workflow belongs to the Subnautica2Modding team and the Mod Tools contributors.