Superintendent George Price says smoking will be prohibited at all six of the park's guarded beaches beginning June 19.
Price tell the Cape Cod Times that secondhand cigarette smoke ''ruins the experience'' of non-smokers at the beach. Millions of people visit the national park every year.
He says the ban is a result of a number of complaints from visitors.
The smoking ban covers Coast Guard Beach and Nauset Light Beach in Eastham, Marconi Beach in Wellfleet, Head of the Meadow Beach in Truro, and Race Point Beach and Herring Cove Beach in Provincetown.