Fix Subnautica 2 Multiplayer Connection Issues

Nothing kills the momentum of a co-op session faster than being stuck on a connecting screen or getting kicked the moment you join your friend. Usually, this happens because you and your friend are running mismatched game versions, or your local network permissions are blocking the game's peer-to-peer handshake.

Why this happens

Early access updates often cause version mismatches that break netcode compatibility. Additionally, Windows Firewall or active VPNs frequently block the outbound traffic required for co-op sessions to initialize.

What you'll need

Administrator access to your PC and confirmation that both you and your friend are ready to check your Steam settings.

Steps

1. 01
   Open Steam, right-click Subnautica 2, go to Properties > Updates, and set Automatic Updates to Always keep this game updated
2. 02
   Close Steam completely by right-clicking the icon in your system tray and selecting Exit
3. 03
   Right-click your Steam shortcut and select Run as administrator
4. 04
   Press the Windows key, type Allow an app through Windows Firewall, and click Change settings
5. 05
   Locate Subnautica 2 in the list and ensure both Private and Public checkboxes are ticked
6. 06
   If the game is missing, click Allow another app and navigate to your Subnautica 2 installation folder to add the game executable manually
7. 07
   Disable any active VPN or proxy software, as these interfere with peer-to-peer networking
8. 08
   Open Steam, go to Settings > Downloads, and click Clear Download Cache to remove corrupted temp files
9. 09
   Right-click the Start button, open Device Manager, expand Network adapters, right-click your active adapter, and select Update driver