Powerboats are available from Extreme Rentals, at the Bayfront Inn Hotel, 1221 5th Ave. South (tel. 239/774-0061; www.extremerentals.us); and from Naples Boat and Jet Ski Rentals at the Port-O-Call Marina, 550 Port O Call Way (tel. 239/774-0479; www.naples-boatrentals.com).
Cruises -- Day Star Charters features the double-decked Double Sunshine (tel. 239/263-4949; www.tincityboats.com), which sallies forth onto the river and bay daily from Tin City, where it has a ticket office. The 1 1/2-hour cruises leave at 10am, noon, 2pm, and an hour before sunset. They cost $25 for adults and $13 for children 11 and under.
The Sweet Liberty (tel. 239/793-3525; www.sweetliberty.com), a 53-foot sailing catamaran, makes 3-hour morning shelling cruises to Keewaydin Island. The vessel then spends the afternoon on 2-hour sightseeing cruises (you'll usually see dolphins playing in the river on this one) and 2-hour sunset cruises on Naples Bay before docking at Naples City Dock, 880 12th Ave. S. Shelling cruises cost $40 for adults, $15 for children 12 and under; sightseeing and sunset cruises cost $30 for adults, $15 for children 12 and under.
For a good deal more luxury, the 83-foot Naples Princess (tel. 800/728-2970 or 239/649-2275; www.naplesprincesscruises.com) has narrated breakfast, lunch, and sunset dinner cruises from Port-O-Call Marina, on the eastern shore of the Gordon River. With their extensive buffets, the sightseeing, sunset, and shelling cruises are good values, ranging from $15 to $54 per person. Prices for children 12 and under vary on all cruises. Call for schedules and reservations.
For a more scientific type of cruise, Sea Excursions (tel. 239/642-6899; www.dolphin-explorer.com) offers an educational experience aboard the scientific research vessel, Dolphin Explorer, on which you will actually work along naturalists to gather data for the 10,000 Islands Dolphin Project (http://dolphinstudy.com). Cost is $54 per person.
The locals like to fish from the Naples Pier. The pier has tables on which to clean your catch, but watch out for the ever-present pelicans, which are master thieves. You can buy tackle and bait from the local marinas. The pier is open round-the-clock, and admission is free. No fishing license is required.
The least expensive way for singles, couples, and small families to fish without paying for an entire boat is on the 45-foot Lady Brett (tel. 239/263-4949; www.tincityboats.com), which makes two daily half-day trips from Tin City for $69 for adults, $35 for kids 11 and under. Rod, reel, bait, and fishing license are included, but bring your own drinks and lunch. For the same prices, its sister boat, the Captain Paul, goes on half-day backcountry fishing trips, departing daily at 9am.
A number of charter boats are based at the marinas; call or visit them for booking information and prices.
Naples has an extraordinary number of fine golf courses. Most are out in the suburbs, though not the flat but challenging 18 holes at the Naples Beach Hotel & Golf Club, right in the middle of town. Nonguests can play here, but should call ahead for a tee time.
Two of the best-known are the Lely Flamingo Island Club and the Lely Mustang Golf Club, both on U.S. 41 between Naples and Marco Island (tel. 800/388-GOLF  or 239/793-2223; www.lely-resort.net). Robert Trent Jones, Sr., designed the Lely Flamingo course; its hourglass fairways and fingerlike bunkers present many challenges. The Lee Trevino-designed Lely Mustang course is more forgiving, but still fun. Former PGA Tour player Paul Trittler has his golf school at these courses. You'll pay a price here in winter, when 18-hole fees are about $145 at Lely Flamingo and $165 at Lely Mustang, including cart and range balls, but they drop progressively after Easter to about $50 in the muggy summer months.
Eagle Lakes Golf Club, on U.S. 41 between Fla. 931 and Fla. 92 (tel. 239/732-5108; www.eaglelakesgolfclub.net), is another winner, with lots of wildlife inhabiting its many lakes (a 16-ft. alligator reportedly resides near the 17th hole). On-site is a driving range, a practice facility, and a restaurant; instruction is available. Wintertime fees are about $39 to $59, but in the off season they drop to $29 or less. Tee times are taken up to 4 days in advance.
Another local favorite is the player-friendly Hibiscus Golf Club, a half-mile east of U.S. 41 off Rattlesnake Hammock Road, East Naples (tel. 239/774-0088; www.hibiscusgolf.com). A pro shop and teaching pro are available. Fees are about $40 to $85 in winter, cart included, and drop to about $35 in summer.
At the intersection of Vanderbilt Beach and Airport-Pulling roads, the Greg Norman-designed 27 championship holes at the Tiburón Golf Club, 2620 Tiburón Dr. (tel. 877/WCI-PLAY [924-7529] or 239/594-2040; www.tiburongolf.com), play like a British Open course -- but without the thick-thatch rough. Greens fees have been reduced in recent years, starting as low as $35 for 18 holes, with cart, on a weekend day. The course is home to the Rick Smith Golf Academy (tel. 877/464-6531 or 239/593-1111) and the Ritz-Carlton Golf Resort.
The area also has several other courses worth playing, most described in the Naples-Fort Myers edition of the Golfer's Guide, available at the chamber of commerce's visitor center (or check the magazine's website at www.golfersguide.com). Online, www.naplesgolf.com is also a good source of information about area courses.
Kevin Sweeney's SCUBAdventures, 971 Creech Rd., at Tamiami Trail (tel. 239/434-7477; www.scubadventureslc.com), which also has a base on Marco Island, teaches diver-certification courses and rents watersports equipment.
In Olde Naples, the city's Arthur Allen Tennis Center at Cambier Park, 755 8th Ave. S., at 9th Street South (tel. 239/213-3060; www.allentenniscenter.com), is one of the country's finest municipal facilities. In fact, it matches those found at many luxury resorts. To play on its 12 lighted Har-Tru clay courts, it costs $12 per adult and $5 for children 18 and under for 1 1/2 hours' play time. Book at the pro shop, which has restrooms but no showers. The shop is open Monday through Friday from 8am to 9pm, Saturday and Sunday from 8am to 5pm.
Naples Watersports, 550 Port A Call Way (tel. 239/774-0479; www.naples-boatrentals.com), will hook you up with WaveRunners, jet skis, and other water toys. Hobie Cats and windsurfers can also be rented on the beach at the Naples Beach Hotel & Golf Club, 851 Gulf Shore Blvd. N. (tel. 239/261-2222); and at Clam Pass County Park, at the end of Seagate Drive (tel. 239/353-0404).
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.