This concept is a one-manned submersible watercraft that can sail both on and under the surface of water. It was developed for the day when, due to increased crowding and pollution, humans will be living on and under the oceans. Then, people will need a new type of underwater transportation, like a submersible craft. The Aqua has a dolphin-like shape that is ideal for moving under the water. The design also explored controlling buoyancy, supplying oxygen and how to protect the driver from water pressure.