The concession-operated snack bars at Watch Hill and Sailors Haven are open seasonally (mid-May through mid-October) at National Park Service facilities. Fire Island Concessions also operates The Pier at Watch Hill restaurant, open weekends during the summer.
If you're planning to visit any time between mid-October and mid-May, or on weekdays from Labor Day to mid-October and mid-May to late June, be sure to verify that food service will be available at your destination. If not, bring along your own food and drink. Most public restrooms on Fire Island are not winterized and thus are closed from late-October through early May.
Fire Island National Seashore is a carry-in, carry-out park, so please plan to pack out your trash. Also be respectful of restrictions in some communities where food and drink are not allowed on the beach or in other areas.
Expect to pay slightly higher prices on Fire Island. Numerous restaurants are located on Long Island.