Dive Site: BOCA do INFERNO

Dive site facts: BOCA do INFERNO

Depth

6–22 m

Current

Moderate, variable

Visibility

3–12 m

Water temperature

13–19°C

Entry

Boat entry

Level

Intermediate

Dive type

Reef, topography, swim-throughs

Region / port

Cascais, Lisbon

Coordinates

38.6892, -9.4294

Conditions & Currents

Diving at Boca do Inferno requires careful planning due to the dynamic Atlantic environment. Surge can become particularly pronounced around narrow passages and shallower boulder fields, requiring divers to maintain excellent buoyancy control. Divers must stay well clear of the churning wash zones near the base of the cliffs where water movement is intense. While general current strength can be variable, moderate currents are possible, particularly in exposed areas, necessitating attention to dive planning and gas management. Visibility typically ranges from 3 to 12 meters, but can be influenced by recent weather and swell conditions. Boat entry is standard, and due to frequent coastal pleasure boat traffic, deploying a surface marker buoy before ascending is a critical safety procedure.

Marine life & sighting chances

Common octopus

common

European conger eel

common

White seabream

common

Ballan wrasse

common

European spider crab

occasional

Dive profile & how the dive runs

Dives at Boca do Inferno typically begin with a boat entry, leading divers into a world of dramatic limestone formations. The profile often involves exploring the rugged reef environment, which features a series of submerged gullies, overhangs, and boulder fields. Divers can navigate through natural rock arches and crevices, directly mirroring the surface's 'Mouth of Hell' topography. Depth progression varies, allowing for shallower explorations around 6 meters or deeper routes down to 22 meters, depending on the chosen path and diver experience. The dive route often involves following the intricate contours of the rock formations, keeping an eye out for sheltering octopuses and schools of sea bream. The turn point is usually determined by air consumption and bottom time, with the ascent conducted slowly. Safety stops are typically performed in shallower, sheltered areas, and divers must deploy a surface marker buoy before surfacing due to potential boat traffic.

Underwater photography

Capturing the unique rugged topography of Boca do Inferno requires careful consideration of lens choice and lighting. Wide-angle lenses are ideal for encompassing the dramatic limestone formations, submerged gullies, and boulder fields, especially when shooting swim-throughs and arches. Due to variable visibility ranging from 3 to 12 meters, photographers should be prepared for green-blue water and utilize strobes to bring out the vibrant colors of encrusting sponges and anemones. For macro subjects like the common octopus tucked into crevices or European spider crabs, a macro lens with a snoot can highlight details against the rocky background. Buoyancy control is paramount to avoid disturbing delicate marine life and stirring up sediment within tight passages. Always respect the environment, maintaining a safe distance from subjects and never touching the formations.

Combine with nearby dive sites

• CANYON do INFERNO

  Features dramatic underwater canyons and rock formations near Cascais.

• BATELÃO

  An advanced dive site off the Cascais coast, often combined with other local dives.

• Pedra do Spinola

  A rocky pinnacle with canyons, known for Atlantic marine life.

Getting there & logistics

Boca do Inferno is located near Cascais, a popular coastal town easily accessible from Lisbon Portela Airport (LIS), which is the largest and most well-connected airport in Portugal. From Lisbon, Cascais is a short drive or train ride, making day trips convenient for divers. Dive operators in Cascais or nearby Estoril provide boat access to the site, as boat entry is the standard method. While there are no specific permits mentioned for this particular site, it is always advisable to confirm any local fees with your dive operator. Dives at Boca do Inferno are typically conducted as part of a half-day or full-day excursion from a local dive center, often combined with another nearby site depending on conditions and diver preference.

Safety & environment

Diving at Boca do Inferno requires adherence to strict safety protocols due to its dynamic nature. The nearest recompression chamber would be in a major medical facility in Lisbon, highlighting the importance of cautious diving and proper planning. Evacuation in case of emergency would involve marine rescue services to transport a diver to the nearest port for onward medical transfer. Comprehensive dive insurance covering medical emergencies and evacuation is strongly recommended for all divers. Site-specific hazards include potential strong surge and moderate currents, especially around narrow passages and exposed areas. Divers must maintain good buoyancy control and situational awareness, staying clear of churning wash zones near the cliffs. Deploying a surface marker buoy (SMB) upon ascent is mandatory due to frequent coastal pleasure boat traffic, ensuring visibility to surface vessels. Always dive within your certified limits and follow your dive guide's instructions.

Who it suits, and who it doesn't

FAQ

BOCA do INFERNO FAQ

Liveaboards diving BOCA do INFERNO

These liveaboards may visit BOCA do INFERNO on selected itineraries, the exact dive sites depend on departure, weather and conditions.

Water And Wind

Portugal

8 guests13 m