In the US you can only work unpaid as a volunteer for a charity or government organization. There is a trainee exception that the feds seem to treat narrowly (see below for six criteria).
The federal law is FLSA. From one of the agency’s fact sheets -
Fact Sheet #14A: Non-Profit Organizations and the Fair Labor Standards Act (FLSA)
Volunteers
The FLSA recognizes the generosity and public benefits of volunteering and allows individuals to freely volunteer in many circumstances for charitable and public purposes. Individuals may volunteer time to religious, charitable, civic, humanitarian, or similar non- profit organizations as a public service and not be covered by the FLSA. Individuals generally may not, however, volunteer in commercial activities run by a non-profit organization such as a gift shop. A volunteer generally will not be considered an employee for FLSA purposes if the individual volunteers freely for public service, religious or humanitarian objectives, and without contemplation or receipt of compensation. Typically, such volunteers serve on a part-time basis and do not displace regular employed workers or perform work that would otherwise be performed by regular employees. In addition, paid employees of a non-profit organization cannot volunteer to provide the same type of services to their non-profit organization that they are employed to provide.
Where to Obtain Additional Information
For additional information, visit our Wage and Hour Division Website: http://www.wage
From a labor attorney web site. The criteria used by the feds for the “trainee” exception -
If all of the following six factors are met, an intern is not an employee, and the FLSA's payment requirements will not apply:
- The training, even though it includes actual operation of the facilities of the employer, is similar to that which would be given in a vocational school;
- The training is for the benefit of the intern;
- The intern does not displace regular employees, but works under their close observation;
- The employer that provides the training derives no immediate advantages from the activities of the intern and, on occasion, the employer's operations may actually be impeded;
- The intern is not necessarily entitled to a job at the conclusion of the internship; and,
- The employer and the intern understand that the intern is not entitled to wages for the time spent in the internship.