The Nature Conservancy

• The Nature Conservancy is an organization founded in 1951 that works to conserve and protect ecologically-important lands and waterways. It works in all 50 states and throughout more than 30 countries. Volunteer opportunities are available in the United States, from restoring an oyster reef in Florida's Indian River Lagoon to protecting native species around Wyoming's Red Canyon Ranch or cleaning up North Carolina's Rumbling Bald Mountain.
  
  

Ripple Africa

• Ripple Africa is a charity organization that develops programs specifically in Malawi. Volunteer placement programs are available involving environmental topics. Potential volunteers need to discuss their skills with volunteer placement officials in order for the organization to put together a suitable project. Environmental projects can include tree planting, the creation of community gardens, constructing fuel-efficient stoves for home use and even beekeeping or fish farming. Previous volunteers have started an environmental club that is still going on through Ripple Africa which, among other things, has established a tree nursery.
  
  

Patagonia Volunteer

• Patagonia is a geographical area covering the southernmost portions of South America, specifically in Argentina and Chile. Patagonia Volunteer is an organization that sets up volunteers in a number of programs based on their skills and interests. Environmental volunteer opportunities are related to the protection of the environment, environmental awareness and sustainable use of natural resources. One program in particular focuses on supporting communities that are affected by non-sustainable mining practices. Another asks volunteers to help local educators put together packets to help spread awareness about environmental problems in Patagonia.
  
  

Reef Check

• Reef Check is a nonprofit organization founded in 1996. It is dedicated to protecting and conserving tropical coral reefs and California rocky reefs. Volunteer opportunities are available for individuals across the globe. Divers can take part in the organization's EcoDiver training course, which qualifies them to work with coral reef survey teams employed by Reef Check in more than 90 countries worldwide. There are also opportunities in outreach, public relations and community organizing. Reef Check's headquarters, located in Pacific Palisades, California, also needs administrative volunteers. More hands-on volunteering opportunities are available to recreational and professional divers, as well as marine scientists.