Subnautica 2 Multiplayer Not Working? Fix!

You are staring at a connection error or getting kicked the moment you try to join your friend's co-op session in Subnautica 2. Multiplayer failures in this title usually stem from version mismatches while in early access or local network permissions blocking the game's handshake process.

Why this happens

Most multiplayer issues occur because your game build is outdated compared to your friend's, or Windows Firewall is blocking the necessary outbound traffic for the game's netcode.

What you will need

Ensure you have administrator access on your PC to modify firewall rules and Steam settings.

Steps

1. 01
   Open your Steam Library, right-click Subnautica 2, and select Properties. Navigate to the Updates tab and set Automatic Updates to Always keep this game updated to ensure you and your friend are on the same build version.
2. 02
   Close Steam completely by right-clicking the icon in your system tray and selecting Exit. Press the Windows key, search for Steam, right-click the application, and select Run as administrator to bypass permission conflicts.
3. 03
   Click the Windows Start button, type Allow an app through Windows Firewall, and click Change settings. Ensure Subnautica 2 has both the Private and Public checkboxes ticked in the list.
4. 04
   If the game is missing from the list, click Allow another app, browse to your Subnautica 2 installation folder, and add the main executable manually.
5. 05
   Open Steam Settings, navigate to Downloads, and click Clear Download Cache to remove stale files that may be interfering with your network connection.
6. 06
   Open Device Manager, expand Network adapters, right-click your active adapter, and select Update driver to ensure outdated network software is not causing packet loss.

Still not working?

If you are still unable to connect, disable any active VPN or proxy services as these force a symmetric NAT type that breaks peer-to-peer handshakes. If the problem persists, perform a clean reinstall of the game by deleting the local files in your Steam installation directory to clear out any corrupted configuration data.

Frequently asked questions

Do I need to be on the same internet connection as my friend?

No, Subnautica 2 uses peer-to-peer networking, so you can play with friends anywhere as long as your firewall and network settings allow the connection.

Will verifying game files delete my save data?

No, verifying integrity of game files only checks for missing or corrupted program files and will not affect your save game progress.