The Sesimbra Coast offers a diverse underwater environment featuring reefs, wrecks, caves, kelp forests, and artificial reefs. Divers can explore depths ranging from 10 to 30 metres, with visibility typically between 5 and 20 metres. The site is suitable for beginners, with both shore and boat entries available. Marine life frequently observed includes common octopus, scorpionfish, European common cuttlefish, and various wrasses. Other species such as tricolor doris, slipper lobster, conger eel, and lefteye flounder are also recorded. Water temperatures remain between 15 and 17 degrees Celsius, necessitating appropriate thermal protection. Facilities include parking, showers, changing rooms, and rinse stations. Night diving is permitted, offering a different perspective of the reef.

Batelão is a sunken barge located near the harbour shelter on the Sesimbra Coast. Once used as a pier for boarding stone, this small wreck sits at a maximum depth of 15 metres. The site is suitable for beginners and is accessed by boat. Divers encounter mild currents and should remain aware of boat traffic in the area. Marine life observed at the site includes common octopus, wrasses, bream, and tompot blenny. Less frequently, divers record European common cuttlefish, scorpionfish, various sea slugs such as the tricolor doris, and flatworms. The surrounding harbour structures also support a variety of local biodiversity.

Pedra do Meio is a reef site located 500 metres off the Sesimbra Coast. The site features a reef structure ranging between 8 and 13 metres in depth, with an average depth of 10 metres. It is suitable for beginner divers, offering mild currents and visibility between 5 and 10 metres. Access is by boat only, and the site supports night diving. Divers should remain aware of boat traffic in the area and follow specific ascent procedures provided by their skipper. Water temperatures range from 15C to 18C throughout the year. As there are no facilities at the site, divers should confirm arrangements with a local operator before travelling.

Maria is a shore dive located on the Sesimbra Coast, offering a combination of reef and seagrass habitats. The site is suitable for beginners, with an average depth of 7 metres and a maximum depth of 8 metres. Divers can expect mild currents and visibility ranging from 5 to 10 metres. Water temperatures fluctuate between 15 and 19 degrees Celsius throughout the year, making a 5mm wetsuit and hood advisable. Entry is from the shore, where caution is required to avoid rocks. The site provides an accessible environment for exploring temperate marine habitats typical of the Portuguese Atlantic coast.

Maria Grécia is a wreck and artificial reef site located off the Sesimbra Coast in Portugal. The site is shallow, with an average depth of 4 metres, making it suitable for beginner divers. Access to the site is by boat only. Divers can expect mild currents and visibility ranging from 10 to 30 metres. Water temperatures fluctuate between 15C and 19C throughout the year. The site offers a straightforward dive experience, typically lasting around 45 minutes. As a wreck and reef environment, the topography provides a distinct structure for exploration within the Setúbal region.

Barco das Telhas is a technical dive site located off the Sesimbra Coast, featuring a combination of wreck, reef, and drop-off topography. Situated at depths between 55 and 65 metres, this site is reserved for expert divers capable of managing decompression and overhead environments. Conditions are challenging, with strong currents and visibility fluctuating between 3 and 15 metres. Water temperatures remain cool, ranging from 14 to 16 degrees Celsius, necessitating appropriate thermal protection. Access is strictly by boat, and divers must remain vigilant regarding entanglement risks within the wreck structure and boat traffic during surfacing. Careful planning is required to navigate the surge and current conditions.

Pedra da Mula is a wall dive located off the Sesimbra Coast, Portugal. The site features a wall that drops into depths ranging from 15 to 25 metres, with an average depth of 20 metres. Accessible only by boat, the site is situated 1000 metres from the shore. Divers encounter mild currents, making it suitable for beginners. Visibility varies significantly, ranging from 3 to 15 metres. Water temperatures remain cool throughout the year, fluctuating between 15 and 18 degrees Celsius. A 5mm wetsuit is recommended for this temperate Atlantic environment.

Penedos is a wall and reef site located 500 metres off the Sesimbra Coast. This site is suited for advanced and technical divers, with depths ranging from 20 to 90 metres and an average depth of 65 metres. Divers must manage moderate currents and occasional surge, which can impact buoyancy control. Visibility typically ranges between 10 and 30 metres. Water temperatures remain cold, between 14 and 16 degrees Celsius, necessitating a drysuit or 7mm wetsuit. Boat access is required for all dives. Species recorded around this area include Mediterranean moray, European common cuttlefish, common octopus, squat lobster, cuckoo wrasse, conger eel, various flatworms, and nudibranchs.