Vacations aren’t just about downtime anymore. More and more of us are taking voluntours, trips that combine fun, adventure and service. Start small, by walking a shelter dog, or dive in – literally- to help clean up the ocean. Here are some ideas to get you started:

Get your exercise and make a four-legged friend when you take a Pound Puppy Hike at Utah’s Red Mountain Resort. Located in St. George, the resort connects willing guests with a local no-kill shelter. You're given doggie treats for your jaunt, and if you fall in love with your walking buddy, you can apply to adopt. Similar hikes with shelter dogs are offered around the country, so ask what’s available on your next trip.

If you’re up for more than a stroll, consider a voluntour to protect and preserve our national parks and other natural resources. On a Yosemite Volunteer Vacation, offered by REI Adventures, you’ll assist park rangers with trail repairs, cutting overgrown vegetation and other chores. The Yosemite trip is offered in May and September, when the daytime temperatures are better for this kind of physical exertion—and for a vacation.

See incredible Machu Picchu, known as one of the Seven New Wonders of the World, on a 10-day REI Adventures tour. You depart from Cusco for a guided tour of this ancient Incan site and other Peruvian cities. Along the way, you’ll be trained on how to repair the trails, clear invasive plants and restore some of the archaeological finds. While you’re soaking up the history and culture of this World Heritage site, you’ll also see unforgettable scenery.

If that trip sounds a bit too strenuous, consider a seven-day Virgin Islands Volunteer Vacation instead. This REI Adventure will have you doing whatever the Virgin Islands National Park needs while you’re there. Tasks might include removing debris or cutting back vegetation, but each work day ends at 4:30 p.m., and the trip includes two “free” days to swim, snorkel or lounge on the beach while you sip a cold drink.

And if beaches are your thing, you can a plunge into voluntourism with Project AWARE, an ocean conservation organization that partners with PADI, the Professional Association of Diving Instructors, in a program called Dive Against Debris.

Dive Against Debris links some 21,000 divers in over 60 countries to help clean up our oceans. Volunteers must be certified as PADI (Junior) Open Water Divers or above, or hold equivalent certification, and they must be at least 12 years old. The program requires taking the Dive Against Debris Distinctive Specialty course. Once it's completed, you'll know how to collect and report on marine debris in waters around the world.

Volunteers who enjoy marine life are needed to help loggerhead turtles on Bald Head Island, off the coast of North Carolina. Visitors can take an evening turtle walk from June to mid-August as part of the island’s conservancy program, or tag along for a nest excavation, when stuck babies are dug out of nest egg chambers. For a real, hands-on experience, apply to become a sea turtle intern or nest monitor before you arrive; see the website for details. Just be aware that voluntour opportunities like these often require a time commitment of several weeks or even months, and aren't intended for short vacations.

If you have enough time, you can also apply to help with sea turtle rehab, work as a turtle docent, or become a sea turtle ambassador in the turtle yard at the Loggerhead MarineLife Center in Singer Island, Florida, an important nesting site. Otherwise, just enjoy a nighttime tour of nesting sites, offered from June into July at the Palm Beach Marriott Singer Island Beach Resort and Spa.

If you’re planning a dive or snorkel trip to Barbados, check in at the Barbados Blue Dive Shop, where on-staff marine biologists help monitor coral reefs in the eastern Caribbean. You can book a trip at the shop to see spectacular underwater sites while you learn about the damaging effects of coral bleaching.

Before you try voluntourism, do some research to make sure it’s right for you. Find out exactly what you’ll be doing on your trip, and which national, international or local organizations may be involved. If you want some traditional vacation time—that is, free days or hours to just relax--make sure it’s included.

Don’t take a voluntour simply because you want a cheap trip. You might save money by splitting meal, transportation and lodging costs with a group, but you may also find yourself sleeping in a tent or driving long distances for food and other supplies. Be realistic about any amenities you’ll be giving up.

Some voluntourism is hard, physical work, and if you’re in an underdeveloped area or underprivileged community, it can be emotionally draining, too. On the other hand, if you match your skills and interests to a need you can truly serve, you’ll have the satisfaction of knowing you made a difference in the world.