How to complete Sunken Antiquities in No Man’s Sky Expedition 6: Blighted

Sunken Antiquities is the fifth Milestone in the third Phase of No Man’s Sky Expedition 6: Blighted. You must acquire an aquatic treasure to complete it, but that’s not a very simple task. This guide explains how to complete Sunken Antiquities so you don’t drown along the way.

Step 1: Find water and deploy the Nautilon

The first thing you need to do is find a planet with some water. This is usually clear from the Discoveries menu, so look at each planet and warp to a new system if you can’t find one with an ocean. When you’ve got one, land on it and deploy the Nautilon using the Nautilon Chamber that you’ll have used to complete Submerged.

Deploy the Nautilon and ensure that you’ve installed the High-Power Sonar. You now need to select the High-Power Sonar from the same menu you access photo mode through. On PS4 and PS5, this is opened by pressing down on the D-pad. Once you’ve selected the device, use it to search for submerged ruins. This will give you the location of some nearby underwater ruins. Follow the new icon on your compass until you reach the ruins.

Step 2: Open the chest

When you arrive at the submerged ruins, interact with the glowing blob you can see. This will give you the Trident Key, which is half of what you need to open the chest at this location. You’ll also need a Living Pearl, which you can pick up from any clams in the ocean around you. This blob won’t complete the Milestone, though.

Next, you need to use your visor to find the chest under this ruin. There should be a hole leading to it, but you may also need to use the Terrain Manipulator to dig your way to it. Use the Trident Key and Living Peal to open the chest and claim a reward. This will complete the Milestone, allowing you to claim 2 Banned Life Support Upgrades and a Hypnotic Eye from the Expedition menu.