Opting in on Steam is quick and doesn't require an access code:
1. Open your Steam Library and right-click Subnautica 2.
2. Select Properties.
3. Go to the 'Game Versions & Betas' tab.
4. In the Beta Participation dropdown, select the Experimental branch.
5. Close the window — Steam will automatically start downloading the update.
You won't need to re-download the whole game; Steam only downloads the difference between your current build and the Experimental one. Once it finishes, just launch the game to play on the Experimental branch.
How do I opt in on Steam?
Updated
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