A propulsion system for a vessel includes an engine propulsion unit that provides a propulsive force to a hull by using an engine as a power source, an electric propulsion unit that provides a propulsive force to the hull by using an electric motor as a power source, a storing mechanism that is displaced from an actuating position to actuate the electric propulsion unit to a storing position to store the electric propulsion unit and performs a storing operation to store the electric propulsion unit, and an interlock controller that interlocks a storing operation of the storing mechanism with generation of a propulsive force by the engine propulsion unit.