Yosemite has a large and vibrant volunteer program, welcoming people from all over the world into positions ranging from visitor information assistants in our visitor centers, to studying rare birds of prey, to picking up litter and building trails. In 2011 over 9,000 volunteers donated over 177,000 hours of service to the park.
The Yosemite Volunteer Program is organized into three basic types of volunteering--individual, groups, and events or drop-in projects. The types of volunteer work vary for each of these, as does the way positions are posted and potential volunteers apply. International Volunteers (those who are not U.S. citizens or permanent residents) must follow some special application procedures. The National Park Service also works with several partners to facilitate volunteering in the park.
Yosemite's volunteer handbook [500 kb PDF] provides more details about working in Yosemite to prospective and current volunteers.
After reading through the volunteer webpages, if you still have questions, please contact the Yosemite Volunteer Program Office at 209/379-1850 or email the volunteer office.