Praia do Cassino, Atlantic beach in Rio Grande do Sul, Brazil

Praia do Cassino is an Atlantic beach in Rio Grande do Sul that runs for many kilometers along the southern Brazilian coast, meeting the city limits of Rio Grande directly. The sand extends as far as the eye can see in both directions, with low dunes behind and a steady surf at the water's edge.

Beach development began in the late 19th century when private companies built hotels and leisure facilities for tourists arriving from inland regions and abroad. The spot grew into a known bathing resort that drew visitors from across South America.

The name "Cassino" comes from the casinos where visitors gambled in the luxury hotels facing the beach, not from a centuries-old gaming house. The Hotel El Aduar, often linked to the name, never operated as a casino. Today the resort-neighbourhood holds a carnival that draws hundreds of people with several carnival groups.

The beach begins at the Molhes da Barra, 22 km from Rio Grande's centre, and the sand runs south toward the Chuí. The Altair wreck lies 16 km from the Cassino neighbourhood, and the El Aduar ruins about 2 km beyond it. A sail-powered cart runs 4.3 km along the west jetty to the lighthouse tower in roughly 20 minutes.

Scientific teams came here during the total solar eclipse of 1966, launching rockets to study the upper atmosphere. The remote location made the beach a suitable site for this research program.