What Is A Posto? by ChrisRJ
In planning a trip to Rio and the beaches you will likely start hearing about Postos. For example, your hotel may be located in Ipanema, near Posto 9. For someone new to Rio this might have about as much relevance as telling an African nomad that you're heading to Sam's Club and does he want you to pick something up for him.Postos are basically small 2 story buildings that look like watch towers, positioned right on the beach near the sidewalk. In them you will find a toilet or two and showers. It costs you about 40 cents to get in. In Copacabana they go from Posto 1 to Posto 6. You then go round Aproador, (which is just an outcrop of rock that has great views for photos), and you're on Ipanema beach that goes from Posto 7 to Posto 12 (when you actually end up in Leblon).
And no, there are no mailboxes at the Postos.