Look carefully at the ads for Caribbean holidays and you will discover somebody's missing. Overwhelmingly, resort brochures feature handsome couples on the beach, usually in a romantic embrace. Presumably some of these couples are married, but where are their children?

A prospective visitor could get the impression that the youngsters are unwelcome in the islands. There certainly can be a hedonistic side to a Caribbean vacation not really appropriate for children, and one recent trend has been toward couples-only resorts.

But many parents enjoy traveling as a family. Is the Caribbean off-limits to them? Not at all.

The fact is, a number of hotels and resorts actually prefer a family clientele to the adults-only crowd. Several have established special rates and an activities program for the youngsters. The kids get a chance to meet new friends their own age, and parents have private time of their own while their children are being supervised by the resort staff.

Even Club Med, the French resort chain that has a reputation for attracting young singles, has introduced "Mini Clubs" and "Baby Clubs" for the youngsters in the family at some of its Caribbean properties.

The Caribbean can be an exciting vacation for all ages: It's fun on the beach, of course, but both parents and children also can enjoy the learning experience of seeing another culture. A variety of ideal Caribbean vacations for everyone in the family is described below.

Good family resorts can be found most abundantly, perhaps, on the island of Jamaica, says Dorothy Jordan, publisher of Family Travel Times, a monthly newsletter that recently surveyed family travel possibilites in the Caribbean. Jordan thinks Jamaica is a good family destination because "there's more to do which will interest everyone," and because "the Jamaicans love children and treat them with loving care and respect."

Families headed for the Caribbean have a variety of options from which to choose the kind of vacation they prefer. "Every family's needs are different," says Jordan.

They can, for example, fly off to one of the big beach hotels, the sort of all-inclusive resort that offers lots of water sports -- snorkeling, sailboarding, sailing -- that appeal to everyone. But where, also, the grown-ups will find fine restaurants, tropical bars and a dance band beckoning them after the youngsters are tucked into bed under the eyes of a sitter.

An alternative is a small beach hotel without the organized nightlife. Here parents and children must rely more on their own resources for entertainment, but this may well be exactly the kind of quiet time together that they are looking for -- a change of pace from busy lives at home.

Other possibilities include camping in the Caribbean, which is the least-expensive way to holiday; renting a vacation home, less costly than it sounds because parents can save on meal expenses by preparing some on their own; and seeing several Caribbean islands aboard a cruise ship that caters to youngsters.

Admittedly, no Caribbean vacation is going to be cheap, since the trip involves air fare to any destination picked. But parents watching a budget may want to avoid remote islands. Connecting flights to them can boost the ticket price substantially.

Hotel rates are much higher during the winter season, generally from mid-December to mid-April. Families who can vacation before Dec. 15 and after April 15 will save a lot of money and not miss out on anything except the crowds. Caribbean weather varies little year round.

One more common-sense budget tip comes from Michael Seligman, who heads FamilyWorld Tours of Hollywood, Calif., a travel firm specializing in family vacations. He suggests choosing a resort where everything -- room, meals, recreational activities -- is included in one "no-extras" price.

The inclusive rate initially will seem much higher compared with a room-only hotel rate, he says. But the family's good humor may disappear -- along with any hoped-for savings -- when the youngsters start begging Mom and Dad for another $5 or $10 for one more sailboard lesson.

Parents tend to be happy when their children are enjoying themselves. And the youngsters are happiest, say Seligman and Jordan, when they have playmates or pals their own age. Here's where families should be able to find that kind of agreeable holiday in the Caribbean:

*Family resorts: For some families, the ideal vacation is one in which members can share activities but also have the opportunity to pursue their own interests. A wide range of recreational facilities that makes this possible can be found at two large Jamaican resort hotels, the Wyndham Rose Hall Beach Hotel and Country Club and Trelawny Beach Hotel. Both hotels, located on the northern shore of the island near Montego Bay, are making strong efforts to attract families.

The recently remodeled Rose Hall is a 500-room hotel with two seven-story towers that overlook the sea in front and the jungle-clad mountains immediately behind. It has the amenities a vacationer expects from a resort: a long beach for water sports; tennis courts; an 18-hole golf course (the front 9 on the sea and the back 9 in the mountains); a choice of restaurants; a weekly beachfront barbecue; and a steel-drum band by the pool.

The Rose Hall also has introduced its Kids Corner, a protected area set aside for youngsters 3 and older and supervised daily year round from 9 a.m. to noon and 2 to 5 p.m. Among the activities, depending on the child's age, are games, storytelling, sand-castle building, crafts lessons, supervised nature walks and free instruction in swimming and snorkeling.

The Rose Hall's low-season rate permits two children, 17 and under, to stay free in their parents' room. During the mid-December to April high season, this is limited to children 11 and under.

The off-season rate ranges from $72 a day for two people for a budget mountain-view room to $110 a day for a deluxe ocean-view room. In high season, the range is $120 to $165. This rate does not include meals.

Like the Rose Hall, the Trelawny is a high-rise resort (350 rooms) with similar beach-front amenities, but it operates on an all-inclusive rate plan that includes most sports year-round and two meals a day.

Among the activities at no extra charge: tennis (including lighted courts); sailboarding, snorkeling, sailing, water skiing and scuba-diving (one free tank dive per day). Supervised children's activities (no charge) for ages 2 to 14 are scheduled daily from 10 a.m. to 4 p.m.

The Trelawny's low-season rate (until Dec. 15) is $68 a day per person for a couple, including breakfast and dinner. There is no extra charge for children 14 and under staying with their parents. The high-season rate is $83 a day per person for a couple. But in high season, there is an additional charge for meals of $19 a day for each child -- but only for children ages 12 and under.

For more information: Wyndham Rose Hall, (800) 822-4200; Trelawny, (800) 223-0888; Jamaica Tourist Board, 866 Second Ave., New York, N.Y. 10017, (212) 688-7650.

*Going camping: Certainly the cheapest way to see the Caribbean is to go camping. But camping on the tiny island of St. John in the U.S. Virgin Islands is far from the rugged outdoors life that might immediately come to mind. It's a nature vacation, away from the casinos and the discos, but with a certain degree of comfort.

A hilly wooded island with good beaches, St. John is only nine miles long and five miles wide. Two-thirds of it is within the borders of the Virgin Islands National Park.

Within the national park are two unusual camping facilities, Maho Bay Camps and Cinnamon Bay Campground, which feature permanent tent-like cottages adjacent to the beach. Guests can stand up and walk around inside these tents.

Each is furnished with beds, chairs, a propane stove, an ice chest, cooking and eating utensils and electric lights. Public toilets, sinks and showers are down the path (this is a camp, after all). Groceries can be purchased at a commissary at each campground.

Both camps provide a full range of water sport facilities, and park rangers schedule nature walks and other educational activities.

Maho Bay's 100 cottages, each a compact 18 feet by 18 feet, are located on a hillside overlooking the beach. They have wood floors and canvas sides. The bedroom is separated by a partition from the living area, where there is a sleeping sofa suitable for two youngsters.

The low-season rate is $40 a night for two people, plus $7 a night for children under 16 and $10 a night for those 16 and over. After Dec. 15, the rate goes to $57 a night for two and $10 a night for any additional guest. During high season, there is a seven-day minimum stay.

Cinnamon Bay is managed by Rockresorts, which operates a number of prestigious resorts in the United States.

Cinnamon Bay's beachside accommodations include 40 large tents and 40 concrete cottages, in which two of the walls are mostly screens. The low-season rate is $22 a day for tents and $29 a day for cottages for two people, plus $6 a day for additional guests. From Dec. 20 to March 31, the rate climbs to $44 for a tent for two and $53 for a cottage. The $6 charge for additional campers remains the same.

The tents and cottages fill up fast in the winter season, so it is important to reserve early.

For more information: Maho Bay Camps, (800) 392-9004; Cinnamon Bay, (800) 223-7637.

*A small hotel: The Bitter End Yacht Club on Virgin Gorda in the British Virgin Islands is representative of the small, choice Caribbean hotels that welcome families (school-age children only here, however) with a "family plan." It's also a good example of how families can save by planning their holiday in the summer.

The Bitter End is a sailor's retreat, and guests have a choice of staying in one of the resort's 33 hillside and beach cottages, amid the hibiscus and frangipani; or in its marina-view rooms; or aboard one of its yachts tied at the marina. Some parents take a room for themselves and put the kids in the less-spacious quarters of a boat.

During the peak season, from Dec. 21 through April 4, the weekly rate for two parents and two children under 16 sharing a marina-view room begins at $3,010, including meals and most activities, such as sailboard lessons. Additionally, there is a $9 per day service charge per person.

By comparison, during the recent low season, May 5 to Oct. 31, the weekly rate began at $2,030, but each family got two rooms for the price. Also, the $9 service charge applied only to parents. Also, during the low season the resort provides free organized afternoon sailing lessons in small sailboats for children ages 6 to 16.

The resort is a bit remote, so getting there is something of an adventure. But the resort's casual style and a fleet of 80 sailboats make it attractive to sailing families or those who want to be.

For more information: Bitter End Yacht Club, (312) 944-5855.

*On a cruise: As floating, all-inclusive resorts, cruise ships can provide parents and children with a variety of activities to appeal to each member's interests. It's a convenient way to vacation.

Many cruise lines make a special effort (youth fares, for example) to welcome families, but none matches the year-round children's program introduced by Sitmar Cruises, says Pam Zirkel of the Cruise Company of Georgetown, a travel agency specializing in cruise holidays.

"They really keep the kids busy," says Zirkel, who has sailed aboard a Sitmar liner, and "there's a snowball effect." Sitmar's cruises draw families, and "the more kids on board, the more fun they have."

Sitmar's 900-passenger Fairwind sails from Fort Lauderdale, Fla., on 8-, 10- and 11-day cruises to the U.S. Virgin Islands, the Yucatan coast of Mexico, Jamaica, Barbados, Martinique and other islands in the eastern and western Caribbean. It carries facilities for infants, young children and teens, staffed from 9 a.m. to midnight.

For infants, there's babysitting; for the youngsters, the activities include ice cream and pizza parties, pool games, movies and crafts instruction; the teens are welcomed in a "Teen Center" with disco dancing (and dancing lessons), fitness training, acting lessons, masquerade parties and sports contests.

Families dine together, and those with younger children are encouraged to sign up for the early sitting at 6:30 p.m. The second sitting, at 8:30 p.m., is a long wait for young appetites.

From April through November of 1986 -- the low season -- a 10-day cruise to Nassau in the Bahamas, the U.S. Virgin Islands, Antigua, Martinique and Barbados -- and roundtrip airfare between Washington and Fort Lauderdale -- begins at $1,695 per adult (double occupancy) for an inside cabin. Outside cabins begin at $2,155 per person.

The low-season rate for children 17 and under (no more than two) sharing a cabin with their parents is $465 each. The youngsters sleep in pull-down upper berths.

The rate for the winter high season (Jan. 29 to March 10 and the Christmas holidays) begins at $1,795 for an inside cabin and at $2,255 for an outside cabin; the youth rate is $980.

For more information, consult a travel agent.

*Your own villa: If space and privacy are important, families can find both by renting a private home or villa in the Caribbean. No need for parents and youngsters to share a room.

Several U.S. firms -- as well as local island companies -- offer rental services. A travel agent or an island's tourist office in New York City can provide a listing.

A villa is excellent for a family that enjoys organizing its own outings. And there can be a big savings on meals, even if the family prepares only breakfast and lunch. And many island villas feature a private swimming pool, an inviting luxury.

For convenience, families should try locating a place within comfortable walking distance of the beach. To create the carefree, barefoot life style of the islands, it helps if you can leave the car parked (or not rent one at all).

Claire Packman, owner of At Home Abroad, a New York-based villa-rental agency, recommends the island of Montserrat for families. It's a small, quiet English-speaking island off the coast of Antigua that has fine beaches, quaint village markets and mountain trails and volcanos to explore.

In the mid-price range, Packman offers a comfortable three-bedroom, three-bath villa on a hillside near the Vue Pointe Hotel for $190 a day (for up to six occupants) during the winter high season. The low-season rate is $135 a day. These rates include daily half-day maid service, and the maid will prepare breakfast and a light lunch.

The beach and the hotel are within walking distance of the villa. But it's no walk at all to the villa's own private pool.

To daydream at a quiet beach or your own hillside pool is close to everyone's ideal Caribbean holiday.

For more information: At Home Abroad, 405 E. 56th St., New York City, N.Y. 10022, (212) 421-9165.