The question of whether someone here in a nonimmigrant visa status can freely engage in volunteer work or an unpaid training opportunity is a complicated one, and needs to be considered on an individual basis. The facts of each situation will differ, and both immigration and employment law rules apply.
Federal and state laws prohibit employers from allowing individuals, including U.S. citizens, permanent residents and foreign nationals, regardless of immigration status, from volunteering in a position that is normally compensated.
Volunteering does not mean working without pay. Volunteering is donating time with an organization whose primary purpose is charitable or humanitarian in nature, without any kind of remuneration. The Department of Labor website contains resources on what constitute legitimate volunteer activities.
The Department of Labor applies a set of criteria when evaluating whether an activity constitutes a legitimate unpaid internship.
Engaging in activities that would be considered employment, without the appropriate work authorization, is a violation of your immigration status, and could threaten your ability to remain in the U.S., and to obtain future U.S. immigration benefits. If you have questions about a proposed activity, consult with your OVIS advisor before accepting an opportunity.