The Blue Keycard is an item found in tier 1 monuments except for the Dome.

Obtaining

This means that you can find one in these monuments: Sewer Branch, Satellite Dish and Harbor.

You can also buy 1 blue keycard from the Outpost for 100 Scrap. Additionally, you can get it by fishing.

Usage

When found, it can be used to gain access to puzzle areas of tier 2 monuments (Water Treatment Plant, Train Yard, Airfield, Power Plant, Arctic research base, and Underwater lab).