This tour, the longest in this guide, is also the most recommended. It encapsulates the very essence of the island -- it's "Puerto Rico in a Nutshell." Because of the island's small size, you can visit not only its three major cities (San Juan, Ponce, and Mayagüez) but also its greatest attraction, the El Yunque rainforest; its finest beach (Luquillo); its offshore islands (Vieques and Culebra); and even its most intriguing man-made attractions, such as the alien-hunting Arecibo Observatory.Start:  San Juan.

Days 1 & 2: San Juan

Take a flight that arrives in San Juan as early as possible on Day 1. Check into your hotel and, if it's sunny, head for the pool or beach directly, stopping only for maybe a pick-me-up coffee and a pastry to go. As surely as there will be hours of sunshine every day on your trip here, at certain times of the year, it can also cloud up for a few hours, so we always recommend enjoying the sun while it's shining (even if it's for an hour or so).

After a quick swim and some sunshine, you can still spend the afternoon in Old San Juan, enjoying some sightseeing and shopping. A 2-hour walking tour covers the important churches, forts, and other highlights. Add another hour or so because you'll want to shop while you explore, and probably stop for refreshment, a rum drink or fresh fruit frappe, at one of the Old City's famous watering holes. The city is also one of the shopping meccas of the Caribbean, with bargains galore, lots of local arts and crafts, and high-profile retail shops.

Visit one of the area's many fine cafes and restaurants for an early dinner. Then return to your hotel for an early evening and a well-deserved rest.

On Day 2, with shopping and sightseeing behind you, prepare for a full day in the sun. Most hotel and resort pools are great, and the beaches in San Juan are glorious white-sand, turquoise-water affairs. For many visitors, that's why they came to San Juan in the first place. Depending on the location of your hotel, the finest beaches are Condado Beach, Isla Verde Beach, and Ocean Park Beach. Enjoy the watersports activities along the beaches of the Greater San Juan area. Of course, there's nothing wrong with spending a day at the beach.

Make it a point tonight to enjoy some of the nightlife of the capital, either bar-hopping, taking in the club or music scene, or going casino gambling. San Juan is one of the nightlife capitals of the Caribbean. There's likely a lot going on right around your hotel; Old San Juan, Condado, and Isla Verde are centers of activity.

Day 3: El Yunque & Luquillo Beach

While still based in San Juan, drive east for 25 miles (40km) to El Yunque for a morning visit. This 28,000-acre (11,331-hectare) attraction is the only tropical rainforest in the U.S. National Forest Service system. Stop first at El Portal Tropical Forest Center for maps and guidance. You're faced with a choice of hiking trails or else driving through. Unless you engage in extensive hiking, you can see some of the forest's greatest beauty in time for lunch.

After a visit to the rainforest, head north toward the town of Rio Grande and follow the signs to Luquillo Beach in the east. There are many roadside signs and kiosks where you can enjoy a tasty but inexpensive lunch. Shaded by tall coconut palms, the beach is crowded on weekends. Surfing, kayaking, diving, and snorkeling are just some of the activities you can enjoy here, along with the golden sands of the beach itself. There are also refreshment stands and a bathhouse as well as toilets. Return west to San Juan for a final night.

Day 4: Las Croabas & Palmas del Mar

The northeast corner of Puerto Rico is a water and sports enthusiast's dream, with sailing, golf, and all sorts of outdoor pursuits. It's not cheap but worth every cent to check into El Conquistador Resort & Golden Door Spa for the day, taking advantage of its vast array of facilities and restaurants, as well as its water park, health club, spa, children's programs, and watersports equipment.

Using the resort as a base, you can explore Las Cabezas de San Juan Nature Reserve, with its famous lighthouse, "El Faro" and untrammeled tropical forest and beaches. There's a marina on site and several more in town, including the Puerto del Rey (the Caribbean's largest and most modern marina). There a beautiful white-sand, public beach, Playa Seven Seas, and a short hike from here is Playa Escondido (Hidden Beach) and Playa El Convento, the start of a 7-mile undeveloped strip of land.

The resort has several fine restaurants, and the village of Los Croabas, a quaint fishing port, has several simple but high-quality seafood restaurants.

Another option would be to continue driving south along the east coast to Humacao and the nearby resort of Palmas del Mar, where you can participate in the best-organized sporting activities in eastern Puerto Rico, ranging from vast tennis courts to scuba diving and golf, along with deep-sea fishing. Palmas also has 3 miles (4.8km) of exceptional white-sand beaches, all open to the public. There are also a large number of places for lunch and dinner at the resort and a good, affordable seafood restaurant serving freshly caught fish.

If you can't afford the prices of these large resorts, there are several smaller inns throughout this area, from Luquillo to Naguabo.

Days 5 & 6: Vieques

Regardless of where you are based for the night, arrive early at the port of Fajardo on Puerto Rico's eastern coast for a 1-hour ferryboat ride to the island of Vieques, the largest of the so-called Spanish Virgin Islands (it is, in fact, a U.S. territory). Check into a hotel here for 2 nights. Resorts and small inns come in all price ranges.

A stopover in Vieques might be the most idyllic spot in your vacation, as the island offers 40 beautiful, white, sandy beaches, all open to the public. Lazy days in the sun aren't the only activities on the island. You can tour the luminous waters of Phosphorescent Bay, join mountain-bike excursions, go fishing from a kayak, take snorkeling trips, or go scuba diving. Fort Conde de Mirasol Museum is an interesting museum housed in an historic fort, and federal authorities operate two wildlife refuges on former military lands. At night Vieques offers a wide range of bars and good restaurants, the best available on any of Puerto Rico's offshore islands.

Day 7: Culebra

From Vieques, you can also ferry over to close by Culebra, which is far more offbeat and undiscovered than Vieques. Though still undeveloped, Culebra facilities have seen substantial upgrades in recent years, and there are many more rooms available and many more quality rooms over the last few years.

Like Vieques, Culebra is chock-full of white-sand beaches, and you can explore the Culebra Wildlife Refuge. Also snorkel here, or kayak, fish, sail, or hike. The best way to explore the island is to rent and drive a jeep -- although most visitors prefer to hang out for the day on one of Culebra's beaches. The main beach is the mile-long (1.6km) Flamenco Beach, an arcing cove with vibrant water and clean sand. The next morning return by ferry to the port of Fajardo for a continuation of the tour.

Day 8: San Juan

On the morning of Day 8, leave Culebra by taking a ferryboat back to the port of Fajardo. From here, drive west to San Juan for an overnight stopover. Because the city is so vast and so filled with amusements, try to use the time to mop up all the shopping, attractions, and nightlife options you missed on your first visit.

Day 9: Ponce and the Southwest

Leave San Juan on the morning of Day 9 and drive 75 miles (121km) southwest to the city of Ponce, the island's "second city." Take Rte. 1 south to Hwy. 52, then continue south and west to Ponce, following the road signs. Allow at least 1 1/2 hours for the drive. Once in Ponce, check into a hotel for 2 nights.

You can spend another few hours strolling through the historic downtown, visiting museums and cathedrals. Another of Ponce's chief attractions, which can easily absorb 2 hours of your time, is the Museo de Arte de Ponce, which is slated to reopen in October, 2010 after a major renovation.

After some shopping and a local lunch in the old town, continue on one of the beach towns to the west, along Rte. 116: Guánica, La Parguera or Boquerón. Heading to the coast today will mean more time for fun in the sun the next day because Ponce has no real beach. The only reason to stay in Ponce is to go out for a great meal and enjoy the entertainment at the Ponce Hilton, maybe squeezing in a round of golf or some pool time in the afternoon before dinner. (If it's a weekend, there could be a concert at the nearby La Guancha, a public marina and boardwalk where harborfront restaurants serve up local treats and drinks.)

Guánica's three lodging options -- Copamarina Beach Resort, Mary Lee's By the Sea and Hotel 1812 -- are among the best in their class for the region, and the town has seven spectacular beaches. La Parguera and Boquerón are considered the "Cape Cod of Puerto Rico," with ample simple, clean lodging options, from small hotels to guesthouses.

If you head out of Ponce on Day 10, you will also be able to spend 2 hours in the afternoon exploring the Guánica State Forest, the best-preserved subtropical ecosystem on the planet. There are 750 plants and rare tree species that grow here, and many trails descend to the beautiful coastline. Grab a fresh seafood meal at a local restaurant by your hotel. Hopefully, there's live music.

Day 10: Mountain Retreat

It's time to head up to the mountains, because you can't spend a week in Puerto Rico without spending a night at one of its country mountain retreats.

You can visit the Toro Negro Forest Reserve, a 7,200-acre (2,914-hectare) park straddling the highest peak of the Cordillera Central, north of Ponce. Visit Lake Guineo or take a hike to the beautiful Juanita waterfalls. You should also have time to visit the other area forest reserve, Monte Estado State Forest in Maricao. There are fine country inns near both reserves. Most also offer traditional Puerto Rican fare. Have a restful night in the clean mountain air.

Day 11: Rincón & the Northwest

Get up early and begin driving up the west coast north of Mayagüez to Rincón. After checking in at a hotel, hit one of the town's famous beaches. If you surf or windsurf, today's the day for it because you are in the surfing capital of the Caribbean. If it's summer, and the surf is down, then the snorkeling is great. Most hotels and guesthouses have fine pools as well.

If it's winter, consider spending some time whale-watching, as it's the season they breach right offshore. It's also possible to rent a boat to take you to Desecheo Island (just offshore) or the much longer trek to Mona Island, some 40 miles off the coast. Called "the Galápagos of Caribbean," the island is inhabited by giant iguanas and three species of endangered sea turtles, among other rare plant, animal, and marine life. (If you want to squeeze this in on a 1-week trip, it would be best to eliminate the mountain retreat or the second day in the southwest.)

Rincón has a number of fine bars and restaurants, with great food and live entertainment. So make sure you have a great meal and some fun on your final night. And you'll want to be sure to watch the sun go down, which is a beautiful thing on the west coast of Puerto Rico.

The following morning, you'll find that it's only a 98-mile (158km) drive northeast back to San Juan, the hub of all the island's major transportation. The nearby Aguadilla airport, however, also has international flight service, so you could squeeze in some more beach time or another attraction (say the Camuy Caves or the Arecibo Observatory) if you do not have to return to San Juan before flying out.

Day 12: Isla Mona

Boat excursions over to this island are not as organized as they should be, but it's worth the trouble to get to Mona, even enduring a difficult sea crossing across Pasaje de la Mona. Most visitors use Mayagüez (covered earlier) as their base for exploring Mona Island, returning to the mainland for the night. Other, more adventurous travelers camp out on the island. Lying some 50 miles (80km) off the Puerto Rican mainland, Mona has been called the Jurassic Park of the Caribbean.

A nature reserve since 1919, Mona has been uninhabited for the past half-century except for day-trippers. Every species from fish-eating bats to wild goats and pigs live here. And of course, the giant iguanas. The environment is beautiful, but potentially hostile because of its wildness. Department of Natural and Environmental Resources rangers are on hand to offer advice and guidance. There are toilets and saltwater showers at Playa Sardinera, but visitors need to bring fresh water. You can go camping, but the itinerary assumes you'd rather return to the comfort of a hotel room in Mayagüez.

Day 13: Mayagüez & the Northwest

Squeeze in some chill time by the pool in this west-coast suburban city. Go explore the beautifully restored downtown area. Highlights include the elegant central Plaza Colón, dominated by a monument of Christopher Columbus, surrounded by 16 bronze statues of courtly ladies, and the historic Yaguez Theater, City Hall, and Post Office. Two huge fires and an earthquake at the turn of the 20th century destroyed much of the city three different times, but there's much fine architecture from the 1920s and later.

You'll also want to visit the city's zoo, Puerto Rico National Parks Zoo, or its Tropical Agriculture Research Station, next to the Mayagüez Campus of the University of Puerto Rico. Anyone can walk through this site for botanical research, whose grounds feature towering bamboo, wild fruit trees, and the various plant species grown here.

After lunch, as you head north out of the city, drive by its historic harbor and warehouse district with a restored Customs House from the 1920s.

You'll be going to the beautiful towns of the northwest coast, most probably Isabela with abundant affordable lodging options right near the coast, about 30 miles (48km) north. It's so close, you'll have time for a quick swim at whatever beach is right outside your hotel or at its pool. There is no bad beach here.

A kind of alternative-lifestyle vibe accompanies the town's surf culture, so the young and young at heart will find great entertainment and live music at area bars.

Day 14: Arecibo, Indian Ceremonial Park & Rio Camuy Caves

As you head east for your return to San Juan, you can take in three wonders of Puerto Rico. The Observatorio de Arecibo, the world's largest and most sensitive radar/radio-telescope, searches the night sky for extraterrestrial life in the universe beyond. In Karst Country, the Caguaña Indian Ceremonial Park in Utuado was built by the Taíno Indians a thousand years ago. The grandest attraction of all, the Rio Camuy Caves, contains the third-largest underground river in the world. With proper timing, all three of these attractions can be explored in 1 day, with time still left for the final drive back into San Juan.

Following your visits, continue to San Juan, at a distance of some 68 miles (109km) to the west. But remember, it's probably also possible to book a flight into San Juan and out of Aguadilla, especially during the winter high tourism season. Again, this would buy you another afternoon on the beach at Isabela.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.