Sorry, but despite the Michael Caine vehicle “Blame it on Rio”, Rio is not a topless beach area.
https://en.m.wikipedia.org/wiki/List_of_social_nudity_places_in_South_America
22. Copacabana Beach
Location: Rio de Janeiro, Brazil
Address: Praça Coronel Eugênio Franco 1
Website: n/a
Fully Nude? No
Stretching from Posto Dios to Posto Seis, Copacabana Beach is the perfect place in Rio to watch tan lines vanish on a warm day. In addition to hosting topless fun, Copacabana Beach also welcomes millions to its annual New Year’s Eve celebration, and the FIFA Beach Soccer World Cup as well. There’s something for everyone, and who can argue with partial nudity? By the way, images of Rio will make you instantly recall Snoop’s video for “Beautiful,” which makes perfect sense because a portion of the video was shot on the beach.