Santa Maria del Mar is a small district of Lima south to the City Center directly at the Pacific Ocean. It is well known for its beaches and attracts many beachgoers every summer. As a lot of them rent apartments during this time, the population of "enormous" 161 citizens (Census 2007) increases considerably.
During the summer months the beaches Playa Grande, Playa Chica and Playa Embajadores have a quite good infrastructure with Snack Bars, toilets, paramedics and additional police presence. Enjoy your time!