Personal watercraft, with their capacity for high speed and easy maneuverability, generate considerable safety and environmental concerns at the national, state, and local levels. These vessels, more commonly known as jet skis and waverunners, are currently present in thirty-two of the eighty-seven units of the National Park System that allow motorized boating. Responding to high accident rates as well as to harms caused to aquatic wildlife and vegetation by the vessels, the National Park Service proposed a general ban on personal watercraft within units of the National Park System. The proposed ban is the first comprehensive solution to personal watercraft use on the national level. It is expected to be finalized sometime in the year 2000. This Comment suggests that such a ban is both legal and desirable. It also suggests that exemptions from the ban should be granted on a very limited basis.