The Aqua Droid was a model of Separatist Battle Droid that fought in the Droid Army for the Confederacy of Independent Systems during the Clone Wars. They were used by the Separatists during the Third Battle of Kamino by General Grievous to assemble Trident Drills from wreckage fallen to the ground from his fleet. They were also used by Asajj Ventress in the attacking of Tipoca City. They were very effective and killed many clones, including Havoc, but also suffered heavy losses in the battle. Later during the war, several Aqua Droids fought alongside Quarren isolationists during an attempted siege of the planet of Dac.
The Aqua Droid had a blue-grey, skeletal, open necked design similar to the B2 Super Battle Droid, and had propellers on their feet to help them travel through the water. Their main weapon was an elongated wrist blaster attached to their right arm. The wrist blaster could alternatively be used as a battering stick to break open the cockpits of aquatic vehicles.