Subnautica 2 ships 78 placeable base-building parts in its May 14, 2026 Early Access build, every one placed with the Habitat Builder tool. The system is a full redesign of the original Subnautica builder: modular seabed habitats that any crew member can extend, with a deeper decoration layer and explicit placement rules instead of free-form snapping.
Each part has a fixed recipe in basic materials. Most pieces cost one to three of Titanium, Strontium, Celestine, Germanium Ingot or Copper Wire; heavier structural pieces and labs cost more. Recipes ship in one of three states: Available from start (a few starter pieces), Locked behind a scan or fragment, or Hidden until a story trigger fires.
Co-op is built into the system from the ground up. A 1-to-4 player crew shares one base and one inventory pool: anyone with a Habitat Builder can drop a corridor, anyone can fill the shared lockers, and the four stations a base hosts (Fabricator, Modification Station, Processor, Biolab) are always available to the whole squad once placed. The Vehicle Bay is built separately as its own dockable module for the Tadpole and future vehicles.
Parts above are grouped by subcategory (Structural, Lighting, Furniture, Storage, Power, Labs, Posters and Decor, Roof and Wall Greebles, Other). When Unknown Worlds ships an icon for a part it appears on the card; when they haven't yet, the card carries the subcategory glyph in the accent colour so the grid still reads cleanly. The list tracks the current Early Access build and updates as patches ship.