“Even people who have money to spend are feeling somewhat a sense of guilt in spending money when reading and hearing of difficult times for so many other people,” said Edward Piegza, president of Classic Journeys, a tour operator based in La Jolla, Calif. “But if they can see their spending is actually having a positive impact in some way, they are more able to justify to themselves that their travel is doing good.”

IN January, Jill Stanley, a retired personal assistant from Washington, took a 12-day Conservation Safari, operated by Abercrombie & Kent as part of its Philanthropic Journeys program. The trip demonstrated joint charity work the company has done with Friends of Conservation, an environmental organization that works with locals to develop sustainable ways of living in harmony with nature. “We did the safari thing,” she said, “but they also took you around to see what A & K and the F.O.C. had done to help the area.”

On the trip, which cost about $10,800 a person, Ms. Stanley visited an orphanage for children whose parents had died of AIDS and spent time with a Masai village and learned about reforestation efforts in the region. “It made me feel good that we were able to plant trees or give in our name for somebody in the Masai Mara,” she said. “It’s much more rewarding than going and sitting on the beach.”

Companies offering more affordable volunteer vacations report that bookings for do-good trips haven’t dropped as much this year as those for more traditional vacation packages. Sierra Club Outings, which offers a series of “service” trips in which volunteers can help eradicate invasive plants in Channel Islands National Park in California ($695) or maintain trails in the Red River Gorge in Kentucky ($375), said its domestic trips were down by 16 percent for the first three months of the year overall, compared with the same period last year. But service-trip bookings were down just 9 percent.

In some cases, volunteer vacations have even been growing. Projects Abroad, which runs volunteer programs overseas, said bookings were up 20 percent this February from February 2008, with some of the travelers recently laid off but others simply looking for vacations that involve service. Options range from teaching soccer in Moldova for two weeks ($1,795) to teaching English in Nepal for three months ($3,295).