Watersports

Many beachside hotels offer watersports concessions that rent rubber rafts, kayaks, and snorkeling equipment. On the calm Nichupté lagoon are outlets for renting sailboats, jet skis, windsurfers, and water skis. Prices vary and are often negotiable, so check around.

For windsurfing, go to the Playa Tortuga public beach, where there's a Windsurfing School (no phone) with equipment for rent.

Deep-Sea Fishing

You can arrange a day of deep-sea fishing at one of the numerous piers or travel agencies for around $220 to $360 for 4 hours, $420 for 6 hours, and $520 for 8 hours for up to four people. Marinas will sometimes assist in putting together a group. Charters include a captain, a first mate, bait, gear, and beverages. Rates are lower if you depart from Isla Mujeres or from Cozumel -- and frankly, the fishing is better closer to those departure points.

Jet Ski Tours

Several companies offer the popular Jungle Cruise, which takes you by jet ski or WaveRunner (you drive your own watercraft) through Cancún's lagoon and mangrove estuaries out into the Caribbean Sea and a shallow reef. The excursion runs about 2 1/2 hours and costs $40 to $55, including snorkeling and beverages. Some of the motorized miniboats seat one person behind the other -- meaning that the person in back gets a great view of the driver's head; others seat you side by side.

The operators and names of boats offering excursions change often. To find out what's available, check with a local travel agent or hotel tour desk. The popular Aquaworld, Paseo Kukulkán, Km 15.2 (tel. 998/885-2288), calls its trip the Jungle Tour and charges $55 for the 2 1/2-hour excursion, which includes 45 minutes of snorkeling time. It even gives you a free snorkel, but has the less-desirable one-behind-the-other seating configuration. Departures are at 9am, noon, and 2:30pm daily.

Dolphin Swims

On Isla Mujeres, you have the opportunity to swim with dolphins at Dolphin Discovery (tel. 998/849-4757; fax 998/849-4758; www.dolphindiscovery.com). Each session lasts 1 hour, with an educational introduction followed by 30 minutes of swim time. The price is $119 (MC, V), with transportation to Isla Mujeres an additional $15. Advance reservations are required. Assigned swimming times are 9am, 11am, 1pm, or 3pm, and you must arrive 1 hour before your scheduled swim time. In Cancún, the Parque Nizuc (tel. 998/881-3030) marine park offers guests a chance to swim with dolphins and view them in their dolphin aquarium, Atlántida. The price of the dolphin swim ($132) includes admission to the park. It's a fun place for a family to spend the day, with its numerous pools, waterslides, and rides. Visitors can also snorkel with manta rays, tropical fish, and tame sharks. It's at the southern end of Cancún, between the airport and the Hotel Zone. Admission is $33 for adults, $25 for children 3 to 11 (AE, MC, V). Open daily from 10am to 5:30pm.

La Isla Shopping Center, Bulevar Kukulkán, Km 12.5, has an Interactive Aquarium (tel. 998/883-0413, 998/883-0436, or 998/883-5077), with dolphin swims and the chance to feed a shark. Prices for interactive encounters and swims start at $110.

Golf & Tennis

The 18-hole Pok-Ta-Pok Club, or Club de Golf Cancún (tel. 998/883-0871; poktapok@sybcom.com), a Robert Trent Jones, Sr., design, is on the northern leg of the island. Greens fees run $120 per 18 holes, with clubs renting for $26 and shoes for $15. Hiring a caddy costs $22. The club is open daily, accepts American Express, MasterCard, and Visa, and has tennis courts.

The Hilton Cancún Golf & Beach Resort (tel. 998/881-8016; fax 998/881-8084) has a championship 18-hole, par-72 course designed around the Ruinas Del Rey. Greens fees for the public are $88 for 9 holes, $121 for 18 holes; Hilton Cancún guests pay $77 and $99, respectively, which includes a golf cart. Golf clubs and shoes are available for rent. The club is open daily from 6am to 6pm.

The Meliá Cancún (tel. 998/881-1100) has an 18-hole executive course; the fee is $35. The club is open daily from 8am to 4pm and accepts American Express, MasterCard, and Visa.

Horseback Riding

Rancho Loma Bonita (tel. 998/887-5465 or 998/887-5423), about 30 minutes south of town, is Cancún's most popular option for horseback riding. Five-hour packages include 2 hours of riding through the mangrove swamp to the beach, where you have time to swim and relax. The tour costs $72 for adults, $65 for children 6 to 12. The ranch also offers a four-wheel ATV ride on the same route as the horseback tour. It costs $72 per person if you want to ride on your own, $55 if you double up. Prices for both tours include transportation to the ranch, riding, soft drinks, and lunch, plus a guide and insurance. Visa is accepted, but cash is preferred.

In-Line Skating

You can rent in-line skates outside Plaza Las Glorias Hotel and in front of Playa Caracol, where the valet parking is located. The jogging track that runs parallel to Paseo Kukulkán along the Hotel Zone is well maintained and safe.

All-Terrain Tours

Cancún Mermaid (tel. 998/843-6517 or 998/886-4117; www.cancunmermaid.com), in Cancún, offers all-terrain-vehicle (ATV) jungle tours for $49 per person. The ATV tours travel through the jungles of Cancún and emerge on the beaches of the Riviera Maya. The 2 1/2-hour tour includes equipment, instruction, the services of a tour guide, and bottled water; it departs daily at 8am and 1:30pm. The company picks you up at your hotel. Another ATV option is Rancho Loma Bonita.