Aqua Drones are Sentry Drones retrofitted for underwater activity. They are armed with two cannons that can fire in shorts bursts and can also fire a sustained energy beam. At close range, Aqua Drones can disrupt Samus's Visor. They maintain the weakness to the Wave Beam present in Sentry Drones. Samus encounters them in the downed Space Pirate frigate on Tallon Overworld.
- "Security mecha adapted for use in underwater areas. The Space Pirates have adapted a number of Sentry Drones for use in liquid environments. These Aqua Drones utilize an arsenal and artificial intelligence suit similar to their 'cousins.' The Pirates have been unable to properly shield these Drones from electrical attack, making them vulnerable to the Wave Beam." — Logbook "Aqua Drone" (Metroid Prime)