Finding the Sanctuary zero base will be one of the earlier missions that will be presented to Subnautica players. The base is far below the spiraling rock formations of the Twisty bridge. Starting from Delta Island, players must go to the Delta Station dock. Seatruck can be crafted and used to save oxygen when the player goes to Twisty Bridges.
After arriving at the dock, the player must head northwest to the Delta Island. You don’t need to dive too deep, because the landmark the player is looking for is near the surface of the water. After about 350 meters from the dock, the player should be able to see a huge looping branch of Twisty Bridges. Swim to the structure, and then descend directly to the biome. Find one of Alterra’s technical sites.
After arriving at the technical site, investigate the surrounding environment. Note the dim, flashing green light. These flashing beacons are the key to locating the Sanctuary Zero base. If the player brings a Seatruck, they may need to leave it here because the vehicle does not perform well at shallow depths.
From here, players can use Seaglider to continue their missions. After finding the beacon, the player must follow the flashing green light through the network of underwater caves and tunnels. Use oxygen plants scattered around the cave. If they follow the correct path, the player will reach the entrance of Sanctuary Zero Base.
After entering the Sanctuary Zero base, Robin meets the architect Al-An, who warns her that the facility is in a critical condition. He mentions that he needs a new host, otherwise he will perish. Robin will provide her PDA as a suitable space for Al-An transfer; however, the architect will misunderstand her proposal and instead upload himself into her brain. Subnautica: Below Zero follow Robin’s journey to build a suitable vessel for for Al-An so that he can leave her head.
When investigating the base, players need to make sure to collect all three available ion cubes. These glowing green crystals will be used to make tools such as ion batteries, Tether Tool, and the Quantum Locker. Players can also use them to build the architect organ needed to build the new Al-An ship. In order to successfully build their new body, players need to create the architect’s organs, the Architect Skeletal Structure, and the architect’s components (Tissue).