Big Scare (El Gran Susto)

Big Scare is the Bat Islands' signature dive — a rocky seamount rising from 30 m to within 6 m of the surface that concentrates one of the Eastern Pacific's most reliable bull shark aggregations. From June through November the cold Papagayo current pushes nutrient-rich water over the rock and draws in 20 to 60 bull sharks (Carcharhinus leucas) that hover at 12 to 25 m depth, often passing within metres of divers on the sand at 28 m. A rusted WWII-era cargo vessel rests on the north side of the rock at 25 to 32 m, encrusted in cup corals and populated by giant moray eels — an unusual combination of shark aggregation and wreck dive. Pacific manta rays make regular passes in the blue water from November through April.