DETAILS: Caribbean National Forest, (787) 888-1810, www.southernregion.fs.fed.us/caribbean
TWO DAYS: EXPLORE PUERTO RICO'S CARIBBEAN
The indolent pleasures of the Caribbean - sunning, sanding, and swimming - occupy the southwest corner of Puerto Rico, a two-hour drive from San Juan. Base yourself at the out-of-the-way Copamarina Beach Resort near Guanica, a palm-shaded compound fronting a nearly mile-long beach. Offshore, an extensive reef keeps the shallow waters calm and provides vivid diving via the resort's PADI-certified scuba center. Copamarina's own launch ferries you to Gilligan's Island, a barrier isle between shore and open sea divided by mangrove channels and favored by barracuda, zebra-, and parrotfish. Take mask and fins to kick against the current in one direction and ride it back the other.
Rise early to hike the coastal path at neighboring Guanica Biosphere Reserve, a rare and pristine dry forest. The ancient coral-bed trail passes secluded swimming coves and wave-struck promontories. The walking is good, the paths well marked, the bird life colorful, but the going can get hot - take mucho water.
In Ponce, acclaimed chef Mark French's restaurant, Mark's at the Melia, serves international fare with a Caribbean flair and is among the chief attractions of Puerto Rico's second largest city. Arrive in town a few hours before dinner to catch the Ponce History Museum and stroll the old-world Plaza de las Delicias, rich in colonial architecture.
Reserve another evening for a dip at Bioluminescent Bay, buoying tiny ocean-borne microorganisms that glow in the dark when disturbed. Show up sometime between 7 and 10 p.m. at the small town of La Parguera to grab a glass-bottomed launch. For big kicks, go bravely with one of the smaller boats that allow you to jump overboard and swim in the neon bay.