The patrol boat is a ship equipped with anti-aircraft weapons, usually deployed from a naval base as part of a defensive setup. Patrol boats, limited as they are to the water, are usually backed up with aircraft and fixed defences.

Patrol boats can also be deployed by Boat Balloon, a known tactic of the Black Hats pirate gang

Patrol boats are considerably more dangerous to other boats than they are to aircraft, but the threat they pose even to their airborne foes should not be underestimated. Their small size and high speed can make them difficult to hit, particularly from a fast-moving fighter.