Carnival Cruise Line has some nice deals on cruises from Miami this summer. They offer a variety of trips in June, July and August.
August 25, 2014: 4-day Western Caribbean cruise on the Carnival Ecstasy. Round-trip from Miami to Key West (Florida) and Cozumel (Mexico). $279 per person.
June 1, 2014: 6-day Western Caribbean cruise on the Carnival Breeze. Round-trip from Miami to Key West (Florida), Grand Cayman (Cayman Islands), and Cozumel (Mexico). $319 per person.
June 1, 2014: 7-day Western Caribbean cruise on the Carnival Conquest. Round-trip from Miami to Cozumel (Mexico), Belize, Isla Roatan, and Costa Maya (Mexico). $339 per person.
June 8, 2014: 7-day Eastern Caribbean cruise on the Carnival Conquest. Round-trip from Miami to Half Moon Cay (Bahamas), St Thomas (US Virgin Islands), San Juan (Puerto Rico), Grand Turk (Turks and Caicos). $429 per person.