The rule requiring passports for travel outside the United States has caused many American families to look to U.S. territories for a Caribbean vacation, namely

Puerto Rico

and the

U.S. Virgin Islands

, says Kyle McCarthy, editor of Family Travel Forum, an online company that has four family-travel publications.

"More and more, parents want a historic or cultural element in addition to beach, and Old San Juan has fortresses and historic monuments," she says. "Kids will be exposed to a foreign language, yet English is common, so that's the best of both worlds."

El Yunque

rain forest

provides a perfect ecological snapshot. An area on the north shore called Dorado has undergone a lot of development recently, and competition has meant good prices, McCarthy says.

St. John

, which is much less developed than

St. Thomas

or even

St. Croix

, is McCarthy's second choice for families in the

U.S. Virgin Islands

because of its combination of good beaches, water sports and historical plantations and gardens.

If passports aren't an issue, McCarthy recommends

St. Lucia

. "It's very lush, has a small rain forest, a small volcano. The

Piton Mountains

are good for hiking, and they have great water sports." It is lightly developed and draws European families, so the children will be exposed to a variety of languages and cultures. The downsides: You'll likely have to take a small plane to get there, and the roads aren't very good.

Kids who are

Pirates of the Caribbean

fans might get a kick out of visiting the

Bahamas' Grand Bahama Island

, where the last two movies in the series were filmed, and

New Providence Island

to check out the Pirates of Nassau Museum. If you want a taste of Disney gone educational, the Atlantis resort on

Paradise Island

will fill the bill. It's big and a bit pricey but filled with activities for kids and teens, including a recently expanded water park.

St. Kitts

and

Nevis

also get high marks for families, because of such well-preserved natural attractions as a lush rain forest, dormant volcanoes, and a friendly, safe atmosphere.

Jamaica

has many activities that children will enjoy, and some resorts will provide a nanny and/or a kids' club. If you plan to spend most of your time inside a resort, safety is not an issue, but it's not the best of islands for cruising around on your own with children.