praia do preventório is a small beach located in niterói, on the guanabara bay side of town facing the charming são francisco (são francisco's harbor).

only 350 meters in length, and together with the adjacent praia da praia da samanguaiá, this beach is often referred to as 'praia da reia grossa,' or beach of the rough sand.

this beach has calm waters, fine white sand, and many palm and chestnut trees along the shore, however it is not a particularly developed or attended beach in the area.