Virginia Beach isn't just a strip of oceanfront sand. The state's largest city offers plenty to visitors at loose ends over summer's last long weekend.

It's a 41/2-hour drive from Washington, so to make sure there's room at the inns, call the city's VISITORS INFORMATION CENTER, 1-800/446-8038.

Although the weather has been pleasant, an occasional October-like breeze can create a chilly atmosphere for sun- worshippers. But the water is still summer-warm, in case you flip the HOBIE CAT you rent on the beach in front of the Ramada Inn north of the Cavalier Hotel. Half-day rentals are $50, lessons $28.

SEASHORE STATE PARK, on U.S. 60 at 64th Street, is equipped with more than 20 miles of bike and jogging trails. While getting some exercise, you can observe the park's wildlife and plantlife in swamps full of bald-cypress trees draped with Spanish moss. The Park's Narrows Marina boat- launching ramp is free, and fishing from the marina is allowed. Camping is also offered. For further information, call the PARK VISITOR CENTER, 804/481-4836.

The VIRGINIA BEACH FISHING CENTER has deep-sea fishing charters for whole or half-days. Tackle, bait and fish bags are furnished, and there are drinks and snacks aboard. Oceanfront cruises to Cape Henry and back on the new MISS VIRGINIA BEACH leave the center daily at 11, 2:30 and 7:30, except Wednesdays and Saturdays, when there are afternoon and evening cruises only. Prices for the cruise are $7 for adults and $4 for children under 12. Fishing charter prices vary. For information and reservations, 804/422-5700.

On Princess Ann Road south of the resort area and east of the court house is the CASHVAN ARABIAN HORSE FARM, open to the public Tuesday through Sunday, from 9 to 11 and from 1 to 4. The farm stables more than 80 Arabian thoroughbreds, some of which are used for show and breeding. Admission is free. 804/426-2572.

Venture to JUNGLE FALLS on General Booth Boulevard and take on the water slide. The most daring of the four slides is Big Banana, followed by Tiger's Tail, Alligator Alley and Pigmy. It's $3 per mat for half an hour, from 9 a.m. to 10 p.m. 804/425-1080.

Several tennis courts are available for public use. The largest is OWL CREEK TENNIS CENTER at South Birdneck Road and General Booth Boulevard, which has 14 lighted courts and a recreation area for children. Proper tennis clothing and reservations are recommended. It's $2 an hour for adults, $1 for those under 19 or over 59. 804/422-4716.

Virginia Beach has four 18-hole GOLF COURSES. Bow Creek on Club House Road, (804/467-2246) and Red Wing Lake on Prosperity Road (804/425-6300) are both city-owned. Lake Wright on Northampton Boulevard (804/461-2246) and Stumpy Lake on Indian River Road (804/467-6119) are private courses that admit the public.

Other attractions include FALSE CAPE STATE PARK, where camping is permitted, and birdy BACK BAY NATIONAL WILDLIFE REFUGE, both at the end of Sand Bridge Road just north of the Virginia-North Carolina border. For information call Seashore State Park, 804/481-4836.

One of the highlights for seafood lovers is THE LIGHTHOUSE RESTAURANT at Rudee Inlet; the food is good and reasonably priced and the service attentive, a rarity at a resort. On Sundays from 10:30 to 2:30 The Lighthouse offers a five- course brunch for $11, children under 12 can eat for half price. 804/428-9851.

On the return trip to Washington, stop and explore the MARINERS' MUSEUM in Newport News, one of the world's shipbuilding centers. Admission is