Centro de Informação em Saúde para Viajantes (Cives), the Travelers' Health Information at Universidade Federal do Rio de Janeiro, offers a list of public health centers in Rio where travelers can get free yellow fever vaccination.
It is recommended that travelers call in advance to check what time vaccination is available.
One of the most convenient locations is the Copacabana health center, more precisely at Praça Serzedelo Correia, a square less than two blocks away from Avenida Atlântica, the avenue along the coast. You can find it easily by searching "praca serzedelo correia rio de janeiro" on Google Maps.
