Portas V was the fifth planet of the Portas planetary system. It was located close to the Demilitarized Zone and was the site of a Breen settlement.

In 2373, the Maquis obtained large cold-storage units from the Breen on Portas V in order to maintain their stocks of the biogenic weapon, cobalt diselenide. Captain Benjamin Sisko discovered the Maquis presence after retrieving the sensor logs of two class-5 intelligence drones stationed in the area. (DS9: "For the Uniform")