A military volunteer (or war volunteer) is a person who enlists in military service by free will, and is not a conscript, mercenary, or a foreign legionnaire. Volunteers sometimes enlist to fight in the armed forces of a foreign country, for example during the Spanish Civil War.
A military recruit who joins by choice is distinct from someone who is forced into service as a draftee, mercenary, or member of a foreign legion. Volunteers might join another nation's military to fight, such as in the case of the Spanish Civil War.