Because of the spoken nature of most traditional master's programs in Spanish, online courses have adapted their offerings to include subsets that do not require such a heavy spoken or listening component. Online classes for a master's degree in Spanish can include courses in linguistics, Spanish language history, Hispanic studies, research and theory of Spanish, or teaching Spanish as a second language. In many programs, you will be asked to choose a particular specialty when you enroll.
A variety of programs have online classes for a master's degree in some aspect of Spanish studies; among these are New Mexico State University, University of Wisconsin-Madison's Online Learning Center and East Carolina University's Spanish Distance Education. Because this is a relatively new field, several of these programs are still in their infancy and thus may develop over the years.
If you have studied Spanish at the undergraduate level, or have learned it through other means, such as by having a bilingual parent or through traveling, an online course in a particular aspect of Spanish can give you the qualifications necessary to teach the language at the high school level. In addition, it will prove your knowledge of the language as you apply for other jobs that require Spanish. An online course provides a great degree of flexibility, as you will usually be able to do most of your work from home.
While online master's degrees in Spanish do offer numerous advantages, they do not provide the same kind of immersion in the language, particularly on an oral level, that in-person classes do. Therefore, because you will be learning at a distance, you will have to make extra efforts on your spoken Spanish.