At a glance
Subnautica has a Mac version: Steam sells it for macOS. The Mac requirements list only Intel: on Apple Silicon Rosetta 2 runs it, and old Mac versions sometimes do not start on current macOS. Try it in Steam for Mac first.
Subnautica came out on Steam on 23 January 2018, made by Unknown Worlds Entertainment.
What your Mac needs
The Mac requirements list only Intel.
Minimum macOS in the Steam requirements: 10.9.
Steam requirements list at least 4 GB of memory for Subnautica; 8 GB recommended.
Allow about 20 GB of disk space for the Mac version.
How to play
Open Steam for Mac and install Subnautica as usual.
If the Mac version will not start, you can install the Windows version through Uncork: download Uncork, sign in to Steam and install Subnautica from there (20 GB). We have not tested it ourselves.
The Windows version through Uncork needs a Mac with Apple Silicon (M1 or newer).
Subnautica uses DirectX 11: Uncork renders it with D3DMetal.