A personal watercraft comprises an oil cooler including an oil cooling passage through which oil circulating inside an engine flows and a coolant passage through which coolant for cooling the oil in the oil cooling passage flows; a first oil passage through which the oil flowing toward the oil cooling passage flows; a second oil passage through which the oil flowing out from the oil cooling passage flows; a bypass passage connecting the first oil passage to the second oil passage so as to bypass the oil cooling passage; and a valve configured to open and close the bypass passage; wherein the valve opens the bypass passage when the temperature of the oil is lower than a predetermined value and closes the bypass passage when the temperature of the oil is not lower than the predetermined value.