Q Are there agencies that cater to single travelers? I'm a widower who'd like to travel on tours or cruises, but most require a substantial supplement unless you agree to share accommodations.

John Robertie

Fairfax

A Several travel agencies deal exclusively with single travelers, and some traditional tour operators offer specific trips for singles. But if you're not willing to share accommodations, chances are you will pay more.

Companies that offer reduced single supplements or will try to match you with a roommate include:

* Singles Travel International (877-SOLO-TRIP, www.singlestravelintl.com). A four-night Caribbean diving trip, without airfare, was recently priced at $595 if matched with a roommate or $795 for a single room.

* O Solo Mio Singles Tours (800-959-8568, www.osolomio.com). A 17-night trip to Portugal and Spain is $2,300 for those who share, and $3,028 for a single room, plus airfare.

If you're active, consider Backroads (800-GO-ACTIVE, www.backroads.com), which has about 80 itineraries for singles. If you sign up at least 60 days in advance, there's no surcharge if it can't find you a roommate. Elderhostel (877-426-8056, www.elderhostel.org), for those 55 and older, often has offerings for singles. Contiki (866-CONTIKI, www.contiki.com), for singles 18 to 35, will set you up with a roommate to avoid the supplement.

Organizations with information about single travel include Connecting . . . Solo Travel Network (800-557-1757, www.cstn.org), which publishes a "Single Friendly Travel Directory" ($5) and offers a yearly membership starting at $28; and Travel Chums (212-787-2621, www.travelchums.com), which will help you find a traveling partner. It's free to join but costs $15 a month for enhanced membership.

For cruises, a few lines, such as Cunard, have single cabins, although they are more expensive than the per-person double-occupancy rate. Upscale lines, such as Seabourn and Crystal, often have good deals for singles. Specialty cruise lines -- including Norwegian Coastal Voyage (800-323-7436, www.coastalvoyage.com) -- are another place to look.

We will be in Rome in late September. Are any churches having concerts? Any other venues for classical music? And are there any opera performances then?

Cherie Bottum

Arlington

While it's not high season for opera or classical music, you'll find several choices in late September.

The opera "La Traviata" will be performed at the All Saints Anglican Church Sept. 25 and on other dates October through December. At the same church, you can see "I Musici Veneziani," featuring orchestra members and singers in 18th-century garb performing various operatic arias; it's offered on various dates through January. A summer classical music concert program goes through Sept. 26 at the ruins of Teatro Marcello. The Tribute to Mozart festival is also being held at the Academy of Santa Cecilia.

Contact Rome Tourism (011-39-06-488991, www.romaturismo.com) for an events calendar. For more info and to buy tickets, contact travel agents Cultural Italy (800-380-0014, www.culturalitaly.com) or Select Italy (847-853-1661, www.selectitaly.com).

My wife and I have been invited to Mazatlan this winter. What's to see and do there? Are there any special travel requirements, such as passports or shots?

Bob Hartnett

Lititz, Pa.

Mazatlan is on Mexico's Pacific coast, north of Puerto Vallarta and across the gulf from the tip of Baja California. It's simpler than a lot of the newer Mexican resort towns that are dominated by expensive hotels and golf courses.

The town is best known for its 17 miles of beaches and historic downtown area, which has undergone extensive renovations. It's also a favorite sportsfishing destination.

Sites worth visiting include the Mazatlan Aquarium, one of the country's largest, and the Archaeological Museum. The Cathedral of the Immaculate Conception, built in the 1800s, and the El Faro lighthouse, the world's second highest, also draw tourists.

Shopping is a popular pastime; the Mazatlan Arts & Crafts Center and the downtown Centro Market are highlights. You can also take day cruises to Stone Island, watch a bullfight at the Plaza de Toros or go for a catamaran ride. For details, contact the Mexico Tourism Board, 800-44-MEXICO, www.visitmexico.com. Another good Web resource is www.pacificpearl.com.

You don't need a passport to visit Mexico, but it's always a good idea to carry one when you leave the country. A notarized copy of your birth certificate and a photo ID are necessary to purchase the required $20 tourist card; the paperwork can be completed onboard your flight. No shots are necessary to visit Mexico.

Send queries by e-mail (travelqa@washpost.com), fax (202-912-3609) or U.S. mail (Travel Q&A, Washington Post Travel Section, 1150 15th St. NW, Washington D.C. 20071).