Writing a volunteer cover letter is a little different than a traditional cover letter that accompanies a resume and job application. Since you are not applying for a specific job, but rather volunteering your services, you will want to demonstrate exactly why you want to volunteer, what your experience is, and what you hope to gain from it. Of course, you should also include what you hope to do for the organization, and why your services would be valuable. Most nonprofits are thrilled to accept volunteers, but applicants still need to demonstrate responsibility and the ability to behave appropriately in the workplace.
It is important to tailor your volunteer cover letter to the specific organization. Chances are, you have chosen an organization based on your interests or your education, and you will want to describe this in the cover letter. Making clear what draws you to the volunteer work, whether it is caring for animals in shelters, cleaning up the environment, or being a mentor for kids, can make it more likely that the organization will offer you the opportunity. In addition to your interests, you will want to share information about your specific skills.
Any nonprofit organization will generally need people to do a few different things. This may involve hands on work, depending on the nature of the organization, or it may involve office work. Almost everyone has some skills that they can highlight in a volunteer cover letter. For instance, if you are great with people, you might solicit donations for fundraising. If you have office experience, you might help to manage or organize an office or answer phones; writing skills or previous nonprofit experience might be used for creating newsletters or assisting with grant writing. Be creative and enthusiastic in your cover letter.
On the other hand, do not lie or exaggerate your experience in the volunteer cover letter. If you are hoping to learn from the organization, say so - many nonprofits are happy to teach skills to willing volunteers. You should also include the amount of time you have to devote to the organization on a daily or weekly basis. Even though you may not be required to show up as in a job, it is very poor form to commit to a certain amount of time with an organization, and then not come in to work. Thank the person reading the letter for that time, and detail if and when you will get in touch with them in the future to discuss the volunteering opportunity.