Can I study while holding a subclass 590 Student Guardian visa?

While the 590 is not a study visa, it does allow some limited study so guardians are not completely restricted. You can enrol in an English Language Intensive Course for Overseas Students (ELICOS) for up to 20 hours a week.

You can also do other study or training, but only for a total of no more than three months. Any study beyond these limits would require a different visa. Your main responsibility remains caring for the student.