To provide a planing boat capable of easily adjusting draft.

This planing boat 1 is provided with a ballast tank 21 provided in a hull, a water supply/discharge port 38 formed on a part lower than a draft line WL, a water supply/discharge valve 37 arranged between the supply/ discharge port and the ballast tank, and an air supply/discharge port 27 connected to the ballast tank by an air passage 26 and arranged on a part upper than the draft line. The upper surface wall 22 of the ballast tank is positioned lower than the draft line. When the boat is advanced in a state where the water supply/discharge valve is opened, water in the ballast tank is discharged from the water supply/discharge port. When the boat is stopped in a state where the water supply/discharge valve is opened, water outside the boat is supplied from the water supply/discharge port to the ballast tank. When the boat is stopped in a state where the water supply/discharge valve is closed, the supply/discharge of water to the ballast tank is stopped.