Many people prefer traveling alone. Unfortunately, the solo traveler is often forced to pay a punishing "single supplement" charged by many resorts, cruise lines, and tours for the privilege of sleeping alone. To avoid it, you can agree to room with other single travelers on the trip, or you can find a compatible roommate before you go from one of the many roommate locator agencies.
Travel Buddies Singles Travel Club (tel. 800/998-9099; www.travelbuddiesworldwide.com), based in Canada, runs small, intimate, single-friendly group trips and will match you with a roommate free of charge. TravelChums (tel. 212/787-2621; www.travelchums.com) is an Internet-only travel-companion matching service with elements of an online personals-type site, hosted by the respected New York-based Shaw Guides travel service. Many reputable tour companies offer singles-only trips. Backroads (tel. 800/462-2848; www.backroads.com) offers more than 160 active-travel trips to 30 destinations worldwide, including Bali, Morocco, and Belize.
For more information, check out Eleanor Berman's latest edition of Traveling Solo: Advice and Ideas for More Than 250 Great Vacations (Globe Pequot), a guide with advice on traveling alone, either solo or as part of a group tour.