To provide a suction pipe structure for a small planing boat allowing a suction system to be longer and therefore achieving the suction inertia of an engine and, in turn, stabilized low-speed performance and high torque.

In the small planing boat which is propelled by the reaction of jetting water pressurized and accelerated by a water jet pump from a rear nozzle and which has the engine E mounted in a body (a deck D, a hull H) under an riding seat S for driving the water jet pump, at least part of the suction system for the engine E is provided extending between a cylinder head 41a of the engine E and the seat S and arranged at a position higher than an upper end Td of the deck D constituting the body, and the bottom face of the seat S is recessed to house at least part of the suction system.