the city lifeguards signal dangerous underwater currents via red flags on the beaches - many visitors interpret the red flags as only referring to the strength of the waves, but in fact the danger can often be hidden in the undertows.

swimmers who find themselves caught in a rip - a current that pulls away from the beach - are best advised to remain calm and swim to the side, paralell to the beach to escape the current, rather than trying to swim against it, which can lead to lifethreatening fatigue.

unexperienced and weak swimmers need to consider the conditions and their ability before entering the water - particularly the ocean beaches can challenge even proficient and experienced swimmers.

bay beaches experience higher levels of pollution than ocean beaches - particularly within 24 hours after heavy rainfall. water quality is closely monitored and made public by the instituto estadual do ambiente- inea provides the suitability's report for several beaches in rio de janeiro, city and state on this link.

facilities vary at many of the beaches and visitors need to investigate their destination in advance to allow for planning of supplies such as refreshments, food, sunscreen and so on. while barracas (umbrellas) for sun protection can easily be hired at many of the urban beaches, this is not the case at the wild and more remote beaches.