Start in the Caribbean itself and sail to the Southern Caribbean islands, with no passport needed to fly in from the US.

Sailing from San Juan puts you in the middle of the Caribbean on day one. The piers are next to Old San Juan, so you can explore the forts and colorful streets before you board.
Because the ship is already in the Caribbean, you'll see more islands in a week, with stops like St. Thomas, St. Maarten, Barbados, Aruba and Curacao.
Upcoming sailings from San Juan, Puerto Rico include Azamara, Celebrity Cruises, Crystal Cruises, Disney Cruise Line, Explora Journeys, Norwegian Cruise Line, Oceania Cruises, Princess Cruises, Regent Seven Seas Cruises, Royal Caribbean, Silversea, Viking, Virgin Voyages and Windstar Cruises. Schedules change by season, so ask me for the latest.
Cruises from San Juan most often visit Southern Caribbean, Eastern Caribbean and US Virgin Islands.
Right now the lowest fare I'm seeing from San Juan starts at $456 per person. Prices change daily, and I watch for drops after you book.
Luis Munoz Marin International (SJU) is about 8 miles from the cruise piers in Old San Juan.
Book with me at Caribbean Breeze Travel. There are no fees, I watch for price drops after you book, and I'll let you know about room upgrade offers when they come up.