With well-preserved reefs and easy points of access, St. Croix's beaches have long been popular for snorkeling. Many of the best spots are near hotels, so gear is often available for rent at beachside sport shacks. Here are some of our favorite sandy spots.

Sandy Point National Wildlife Refuge
www.fws.gov/Caribbean
Boasting the longest and most pristine stretch of sand on St. Croix, Sandy Point is the island's best beach for good reason: The site is a federally protected national wildlife refuge, and is open only on weekends. It's home to more than 100 species of birds and is a nesting site for leatherback turtles. It's not the easiest place to find, but once you get there you'll be rewarded with two miles of powdery sand and some of the clearest water in the Caribbean. Head west on Melvin Evans Highway and continue straight at the turnoff for Frederiksted. Drive past the sign for Sandy Point National Wildlife Refuge and follow the dirt road for about two miles to the end. Be sure to bring plenty of water and a picnic, since there are no concessions anywhere near the beach.

Open Saturdays and Sundays 10 am to 4 pm.

Cane Bay
Cane Bay, on the north shore about 20 minutes west of Christiansted, is a shady family-friendly beach. It's also popular with divers, who come here for the Wall, a massive coral shelf that drops to depths of 3,200 feet a mere 100 yards from the shoreline. Book a dive at nearby Cane Bay Dive Shop; the experienced outfit takes beginners and experts to more than a dozen sites along the Wall and beyond (North Shore Road, 800-338-3843; canebayscuba.com). When you're back on land, grab a cool drink at Off the Wall, a super-casual beach bar that lives by the slogan, "No shirt, no shoes, no problem!" (North Shore Road, 340-778-4771).

It's hard not to find a quiet cove to call your own on idyllic St. John. A drive along North Shore Road will take you past dozens of secluded spots, all with crystal-clear water, sugar-white sand, and shady coconut palms. Here are three of our favorites.

Trunk Bay
Mainly due to its proximity to Cruz Bay—it's only a five-minute drive from the port town—Trunk Bay is St. John's most popular beach. But much credit should also be given to the powdery white sand, luxuriant palms, and well-marked snorkel trail that's great for beginners (underwater signs teach you about the marine life you'll spot along the way). In addition to lifeguards, you'll find picnic tables, a snack bar, bathrooms, showers, and snorkeling gear rentals—well worth the $4 admission fee (it's free after 4 pm).

Caneel Bay Beach
Even if you're not staying at Caneel Bay resort, you can still laze on its fabulous namesake beach. You'll have to bring your own towels, and steer clear of the guest-only chaise longues, but you'll have access to the open-air restaurant for a quiet beachside lunch as well as to one of the prettiest little coves on St. John. Adventurous snorkelers can hop in the water (BYO gear, too) and paddle to secluded Honeymoon Beach. It'll take strong swimmers about 30 minutes to get there, but once ashore you'll be rewarded with a slice of sand all your own. If you're not exhausted yet, explore the headland between Honeymoon Beach and Solomon Beach—the next bay over—for a closer look at the reef fish that hug the coast.

Cinnamon Bay
Best known for its affordable beachside camping (campsites from $30 per night; 340 776 6330; www.cinnamonbay.com), Cinnamon Bay offers lots more than rustic screened-in cottages. Featuring the longest beach within the Virgin Islands National Park and strong afternoon breezes, the bay is a popular spot for windsurfing. Get a two-hour introductory lesson from Wind 'n' Surfing Adventures, located right on Cinnamon Bay beach (340-626-4769; $125; windnsurfingadventures.com). If balancing on a board is not your style, rent a kayak and paddle out to one of the bay's five premier snorkeling sites; hop in the water and tow your kayak on a lanyard attached to your ankle for an up-close glimpse of giant brain and elkhorn coral plus plenty of flounder, parrot fish, barracuda, and other exotic fish.

The majority of the beaches on St. Thomas are home to hotels—so expect to compete with other visitors for your own strip of sand. Nonguests are permitted, though some resorts charge a small fee for a beach chair if you're not staying at the property. Here are our favorite two beaches on the island.

Magens Bay
If you avoid this one-mile crescent between 10 am and 2 pm—the height of the cruise ship day—Magens Bay can be every bit the unspoiled strip of sand all those "best beaches" lists make it out to be. The water is consistently calm and there are tons of palm trees for a shady respite, making it a great choice for families. It's overseen by Magens Bay Authority, a private entity that charges $4 per person and rents lounge chairs and nonmotorized water-sports gear. The same authority also maintains the stunning overlook at Drake's Seat, found off Route 40 near the bay, and the romantic though mostly unknown Lindquist Beach near Sugar Bay.

Coki Point Beach
On the island's northeastern coast, not far from the Red Hook ferry dock, Coki Point Beach is another watery stretch that regularly fills with tourists eager for a day in the sun; it's also one of St. Thomas' best snorkeling spots. In order to rent gear at one of the shoreline vendors (where you can also buy fish food), you'll have to wind your way through hair braiders trying to make a buck and food stands selling fried meat patties. But it's worth it for a look at the vast underwater ecosystem, which has angelfish and snapper plus several varieties of coral. For a look at the fish without getting wet, consider visiting nearby Coral World Ocean Park, which features a three-tier underwater observatory that plunges 15 feet below the sea (6450 Estate Smith Bay; 340-775-1555; coralworldvi.com).

Looking at the azure water from your beach chair is perfectly nice, but it can't beat flying across the waves to explore neighboring islands and undersea worlds. Choose your own adventure by chartering a day trip on a luxury power boat. Selecting the right charter company depends on your budget and whether you want a private or semi-private trip. Keep in mind that on semi-private trips you might have to compromise with your fellow passengers on where you travel and how long you will be there. Captains can help plan your day, but some can't-miss attractions include snorkeling off Lovango, hitting the beach on the teeny island of Sandy Spit, a jaunt to the Soggy Dollar beach bar on Jost Van Dyke, and lunch at floating pirate ship Willy T's off Norman island.

Here are our favorite charter companies:

Blue Tang Yacht Charters
Tel: 340 776 9070

Magic Moments
Tel: 340 775 5066

Sandspur Charters
Tel: 340 775 3142

Declared part of the National Park system by John F. Kennedy in 1961, this 176-acre island off St. Croix's northeastern coast is surrounded by nearly 20,000 acres of protected barrier reef, making it perhaps the best spot in the Virgin Islands to go snorkeling. To get there, climb aboard one of two catamarans operated by Big Beard's Adventure Tours (44A Queens Cross Street; 866-773-4482; www.bigbeards.com). All snorkeling gear is provided, and once underwater, you'll be treated to stunning views of brain and elkhorn coral, massive sea fans, and tropical fish of all kinds, including parrot fish, schools of blue tang, and more.

With restaurants, dozens of shops, and enough bars to keep you busy every night of the week, it's not hard to see why the U.S. Virgin Islands' capital city is the most visited Caribbean port of call. Though it's easy to spend the whole time snapping pictures of the gorgeous harbor—and ducking the cruise ship crowds—you'll want to visit attractions like Fort Christian, the oldest standing structure in the Virgin Islands (it dates to 1672 and now houses a museum); the Emancipation Garden and Market Square; and of course, the stores. Though they now stock everything from rubies to surf shorts, these restored trade warehouses once held rum, spices, and molasses.

St. Croix's commercial heart—and the former capital city—was once a Danish trading center, and still has the colorful 18th-century buildings (painted bright yellows and blues) to prove it. You'll find your bearings easily, as every street slopes down toward the waterfront. Highlights include the Danish Customs House, Scale House, Government House, Steeple Building, and Fort Christiansvaern, a former Danish stronghold completed in 1749 that's open for self-guided tours. Looking to cool off while in town? Hop aboard the $4 ferry that departs in front of the Customs House for nearby Protestant Cay, a tiny islet about two minutes away that's home to a hotel, bar, restaurant, and Christiansted's only swimming beach.

There are more than 20 worthy trails within the Virgin Islands National Park, but no serious eco-adventurer should miss the day trip to Reef Bay, on St. John's southern coast. One of the few trails with ranger-led hikes, this easy three-mile, mostly downhill trek features much more than flora and fauna: You'll hike past plantation ruins and petroglyphs, visit a former sugar factory, and wind up at the beach for a dip. Best of all, a boat zips you back to Cruz Bay so you don't have to haul yourself back up the mountain to the trailhead. The hike begins at 9:30 a.m. at the national park visitor's center. Reservations are essential (contact ext. 238 for schedules; $21, including water shuttle).

For one of the best views in all of St. John, don't miss the cactus-studded hike to Ram Head on the island's southeastern tip. Drive to Salt Pond—nearly four miles south of Coral Bay—and follow the quarter-mile path to Salt Pond Beach. From there you can pick up the 1.2-mile Ram Head Trail, which ends with a sweeping island panorama 200 feet above the Caribbean. Low-impact hikers will appreciate the half-mile loop at Cinnamon Bay. The nature walk begins across the road from Cinnamon Bay Campgrounds and is clearly marked with signs identifying animals and trees you'll spot along the way. Finally, history buffs can check out the Annaberg Historic Trail, an easy half-mile walk that passes through one of the island's best-preserved 18th-century plantations. You'll see a partially restored sugar factory, the remains of an old windmill, and what's left of buildings that once housed island slaves.

With his 15 surefooted horses, Stephen O'Dea leads riders of all skill levels around St. Croix's north shore. Depending on his mood, you may be climbing an embankment, negotiating a rocky path down to a beach, or even taking your steed into gently breaking waves. Ladies, be warned: If you let on that you're even the least bit daring, O'Dea might convince you to stand up on your saddle. Some sunset and moonlit trips are available. It's best for children to be at least six years old for them to ride.

Much like the glassed-in gondolas that operate at ski resorts worldwide, the Paradise Point Tramway takes passengers from Havensight near downtown Charlotte Amalie to a 700-foot overlook atop Flag Hill. Stay in the eight-passenger tram for a 15-minute round-trip ride, or disembark at the summit and enjoy the view. You're guaranteed to see nearby Hassel and Water islands, and on a clear day you can spot Puerto Rico, Vieques, and Culebra. There's a bar and restaurant at the top (order a bushwacker, a potent frozen drink made of Bailey's, Kahlúa, rum, Amaretto, vodka, and crème de cacao), plus more shops, if you haven't already emptied your wallet in town.

Open daily 9 am to 5 pm (when ships are in port). Call ahead.

More than 1,500 native and introduced species flourish here amid the well-preserved ruins of a 19th-century slave village. There's also an orchid greenhouse and a "rain forest" area (it's helped along by misters). As you wander the grounds, keep a safe but watchful distance from the "monkey no climb" tree (it has a spiked trunk) and the "touch me not" plant (it has thorns on its leaves). Sweeny Toussaint (St. Croix Safari Tours; 800-524-2026; www.gotostcroix.com/safaritours/index.htm; sjtouss@hotmail.com) leads informative tours of the fragrant, 16-acre estate; he'll offer samples of local fruits like sweet lime and help you choose a fallen mango to snack on later.

Though we're not generally fans of vehicular tours, it's worth getting to see large stretches of St. John, which is two-thirds national parkland—and therefore still pristine. As soon as you pass the National Park Services entrance kiosk, nature takes over (the park is home to more than 800 plant species). Like its two sisters, the island has plenty of red-and-white-striped open-sided safari buses that make the hilly ride even more thrilling. Levi Liburd (L&L Jeep Rental; 340-776-1120; www.bookajeep.com) knows the best photo spots, the history of the Annaberg Sugar Mill Ruins, and possibly more about Virgin Islands botany than anyone else you'll meet.

This restored sugar estate lets visitors peek into St. Croix plantation life during the 18th century. Stretching across 12 acres, the grounds encompass an oval-shaped great house (note the surrounding moat that was used for cooling, not defensive purposes), bath house, windmill, and several other buildings. The guides are especially humorous and knowledgeable; it's worth waiting for one of the intimate tours of the main home. Check the Web site for details on the evening Candlelight Concerts, the only classical music series performed on St. Croix.