Indeed, if you enroll in the MMS Master you will be a student of the University of Girona with all the rights. Accordingly, you will have access to the University facilities, such as the Library, Sports Service, Renting of bikes, in the conditions established for the university students.
During your registration of the MMS master, there is the option of choosing the registration to the Sports Service. It has a low cost which can be lookup in this link.