Dive Site: Gran Susto (Big Scare)

About Gran Susto (Big Scare)

Gran Susto, or "Big Scare," is an advanced boat dive located within Santa Rosa National Park in Costa Rica's Bat Islands. This dive site is renowned for thrilling encounters with bull sharks, making it a world-class destination for experienced divers seeking an adrenaline rush. The topography features volcanic rock formations, and the site functions as a cleaning station for bull sharks, especially between depths of 15 to 30 meters. It offers a deep, open-ocean feel, situated about 30 miles northwest of Playas del Coco. Diving Gran Susto often involves strong currents and surge near the surface, calling for quick descents and conservative dive planning. Visibility typically ranges from 6 to 30 meters, though conditions can be variable. Divers explore the volcanic rock structures, often encountering massive bull sharks that can reach up to 3.5 meters in length. Beyond sharks, the site teems with barracudas, eagle rays, turtles, and large schools of tropical fish. Due to potentially strong currents, deep profiles, and the nature of diving with large predators, Gran Susto is exclusively for advanced divers. It requires strong buoyancy control, experience with deep diving, and the ability to manage rapid air consumption, especially when surrounded by inquisitive sharks. The site offers unique thrills, making it a bucket-list dive for those prepared for its challenges.

Dive site facts: Gran Susto (Big Scare)

Depth

15–30 m (50–100 ft)

Typical dive

15–30 m, 40–50 min

Current

Strong and unpredictable

Visibility

6–30 m (20–100 ft)

Water temperature

24–30°C (75–87°F) May-Dec

Entry

Back-roll / negative entry

Level

Advanced Open Water + deep dive experience

Dive type

Pelagic, drift, shark encounters

Night dive

Not typically offered

Region / port

Bat Islands, Santa Rosa National Park

Coordinates

10.8565, -85.921

Conditions & Currents

Diving at Gran Susto regularly involves strong and often unpredictable currents, demanding excellent buoyancy control and the ability to maintain position. Divers should be prepared for potential surface swells and a mandatory swift descent upon entry to avoid being swept away. A drifting safety stop is common, as there are no fixed lines or points of reference. The site's remoteness means an hour-long boat ride to the nearest medical facility, emphasizing the need for conservative dive profiles and gas planning. Visibility can vary from 6 to 30 meters, often influenced by nutrient-rich upwellings that attract marine life.

Marine life & sighting chances

Bull Shark

May–Nov (peak Jun–Oct) · common

White-tip Reef Shark

occasional

Eagle Ray

common

Giant Oceanic Manta Ray

May–Jun, Sep–Nov · occasional

Barracuda

common

Moray Eel

common

Sea Turtle

May–Oct · occasional

Octopus

May–Sep · occasional

Humpback Whale

Jul–Oct · rare

Dive profile & how the dive runs

Divers typically execute a swift back-roll entry from the boat, followed by a negative descent to quickly reach the desired depth range of 15 to 30 meters. The main objective is to position yourself near the volcanic rock formations that serve as cleaning stations for bull sharks. The dive involves navigating strong currents while observing the pelagic action. Divers should maintain conservative bottom times due to the depth and potential for rapid air consumption in challenging conditions. The turning point is usually dictated by air supply or no-decompression limits, after which a free ascent is made, concluding with a drifting safety stop, as there are no fixed lines available.

Underwater photography

Capturing the impressive bull sharks at Gran Susto requires a wide-angle lens due to their size and the potential for close encounters. Fast shutter speeds are essential to freeze action in unpredictable currents. Consider using external strobes to enhance color and definition in varying visibility conditions. Given the deep profile and strong currents, maintaining good buoyancy is paramount to avoid disturbing the environment and to position yourself effectively for shots. Be mindful of subject etiquette, giving the sharks space and avoiding any disruptive movements. Patience is key, as conditions can change rapidly.

Combine with nearby dive sites

• Bajo Negro

  Remote Bat Islands pinnacle with sharks, rays, and schooling fish.

• Black Rock

  Volcanic pinnacle offering schools of fish, white-tip reef sharks, and eagle rays.

• Monkey Head

  Papagayo pinnacle dive known for easy routes and ray sightings.

• Virador

  Volcanic pinnacle drift dive with diverse marine life.

• Catalina Grande

  Home of Pacific Giant Mantas among other marine life.

Getting there & logistics

Access to Gran Susto is primarily via liveaboard trips or specialized day boats operating out of Playas del Coco, Playa Hermosa, or Ocotal in Guanacaste. Divers typically fly into Daniel Oduber Quirós International Airport (LIR) in Liberia, followed by a ground transfer to the departure port. Liveaboards to the Bat Islands often offer 3-4 guided dives per day, including possible early morning or night dives, and provide accommodation on board, eliminating daily returns to port. The journey to the Bat Islands takes approximately an hour from nearest departure points. A park entrance fee is required as the site is within Santa Rosa National Park. It's often combined with other local dives, with Black Rock being a common second dive.

Safety & environment

Diving Gran Susto demands conservative planning due to its remote location; the nearest recompression chamber is approximately an hour away from the site. Comprehensive dive insurance covering dive accidents and potential evacuation is mandatory. Site-specific hazards include strong and unpredictable currents, significant surface swells, and deep profiles, requiring advanced diving skills, excellent buoyancy control, and efficient air management. Divers must follow strict briefings from experienced guides, especially concerning interactions with bull sharks. It is crucial to maintain a safe distance and avoid any actions that could provoke marine life. Only certified Advanced Open Water divers with genuine deep diving experience are permitted, and many operators require a local warm-up dive beforehand.

Who it suits — and who it doesn't

FAQ

Gran Susto (Big Scare) FAQ

Liveaboards diving Gran Susto (Big Scare)

These liveaboards may visit Gran Susto (Big Scare) on selected itineraries — the exact dive sites depend on departure, weather and conditions.

Cocos Aggressor

Costa Rica

22 guests37.8 m

$636/day

Sea Hunter

Costa Rica

20 guests

$690/day

Okeanos Aggressor II

Costa Rica

24 guests36.6 m

$504/day