• U.S. Dive Travel Offering vacations at dive resorts, luxury live-aboards, and customized eco-tours in many countries.

• U.S. Helicopters Provides sightseeing tours and charters leaving from Long Beach Airport. Offers helicopter flight school and flight training in the R-22/R-44.

• UC Tours Specializing in African American tours.

• Ujamaa Travel Features tours through Tanzania, places to stay, and ecotourism information for worldwide destinations.

• UK Tours & Travel Offers themed group tours to the United States from the United Kingdom.

• Ulendo Safaris Offers group and special interest safaris, itinerary planning, and charter flights.

• Ulinda Safari Trails Camping and luxury lodge safaris to remote secluded areas of Botswana.

• Ultimate Africa Safaris Offers budget camping to lodge safaris.

• Ultimate Dive Travel Specializes in diving vacations.

• Ultimate Travel Group Offers a variety of golf and ski tour packages.

• Umiak Outfitters Canoe, kayak, and snowshoe tours for all ages and abilities.

• Umkulu Adventures Adventure overland, safari, and rafting company in southern Africa that specialises in budget orientated outdoor adventure holidays for independent travellers.

• Uncharted Outposts International Offers custom adventures to remote private ranches, tented camps, and intimate lodges in Africa, Australia, and Argentina.

• Uncommon Journeys Luxury rail and ocean liner voyages.

• Uncommon Journeys Ltd. Offers tours of Canada's Yukon by dogsled and canoe.

• Undersea Expeditions Gay and lesbian scuba diving tours.

• Undersea Explorer Extended scuba diving trips to the Great Barrier Reef and Coral Sea ex Cairns, Australia.

• Undersea Hunter Offering liveaboard diving vacations around Cocos Island.

• Uni Crystal Holidays Offers trips within India, Nepal, and Bhutan.

• Uni Galapagos Offering Galapagos tours, cruises and diving tours, Amazon and adventure tours, trekking, and climbing.