With its charmingly colored colonial buildings, historic seafront forts, and vibrant downtown, Old San Juan makes for one perfect cruise port. There's more than enough fun for a day or two, and much of it is within walking distance from the modern cruise terminal. Savor a variety of Spanish specialty dishes in the many cafes and restaurants. Sample local rums on distillery tours. If you're feeling lucky, go on a winning streak at one of the glamorous casinos.

As exciting as Old San Juan and its modern companion part are, you don't want to miss a day trip to see some of Puerto Rico's other attractions. Plenty of wonderful beaches await near San Juan, but why not take a catamaran to an offshore island like Vieques for secluded white-sand beaches and snorkeling in coral reefs and bioluminescent bays? If nothing else, go hiking in the El Yunque Rain Forest to witness its spectacular waterfalls.