A jet propelled watercraft includes a prime mover, a jet pump driven by the prime mover and jetting water from a jet port, a reverse gate changing a direction of the jet flow jetted from the jet pump, a shift actuator capable of moving the reverse gate to a plurality of shift positions, a reverse gate operator configured to set a position of the reverse gate, and a controller configured or programmed to prohibit startup of the prime mover when it is determined that the reverse gate operator is being operated.