Big Hill Sea Caves on Entry Island features towering red sandstone cliffs and deep sea caves accessible by boat. This reef site is suited for advanced divers due to hazards including overhead environments, surf, surge, and moderate currents. The site reaches depths of 1 to 10 metres, with an average of 5 metres. Visibility ranges from 3 to 10 metres. Water temperatures are cold, fluctuating between -1°C and 18°C throughout the year. The base of the cliffs provides a dynamic environment for snorkelling, though boat access is required to reach the site located 500 metres from shore.

Plage du Port on Entry Island provides a sheltered shore entry point located just south of the main ferry pier. The site features a mix of sandy and rocky bottom topography, making it a practical location for beginners to practise snorkelling. Water temperatures are cold throughout the year, ranging from -1°C in winter to a summer peak of 19°C in August. Visitors should expect brisk conditions, with summer averages typically between 10°C and 18°C. On-site facilities include toilets and a cafe, providing convenient support for those accessing the water from the shore.

La Cormorandière Islet is a rocky reef located off the northeast tip of Entry Island. The underwater topography is defined by rugged terrain, featuring large boulders and deep crevices. This site is suitable for advanced snorkellers due to the presence of strong currents and surf. Access is exclusively by boat, with typical sessions lasting around 45 minutes. Water temperatures fluctuate significantly throughout the year, ranging from -1C in late winter to 19C in August. Facilities including a cafe and toilets are available on Entry Island. As a marine environment, the site supports a variety of general marine life and invertebrates within its rocky habitat.

Lighthouse Beach on Entry Island offers a shore-entry point for snorkelling among rocky shallows and kelp forests. Located on the southern side of the island near the historic lighthouse, the site features a rocky and gravel shoreline. Conditions are variable with moderate currents and visibility typically ranging between 2 and 3 metres. Water temperatures fluctuate significantly throughout the year, reaching a maximum of 19C in August and dropping to -1C in late winter. Due to the cold water, potential for entanglement in kelp, and surf, this site is best suited for intermediate snorkellers. The habitat supports a variety of temperate marine life and invertebrates typical of the region.

Les Demoiselles is a wall dive site located at Entry Island, featuring the underwater extension of red clay and gypsum cliffs. The site is suitable for intermediate divers due to the presence of strong currents and potential surf conditions. Access is available via both shore and boat entries. Water temperatures fluctuate significantly throughout the year, ranging from -1C in late winter to 19C in August. Parking facilities are available for visitors. While the site offers opportunities for both diving and snorkelling, users should be prepared for the challenging current conditions characteristic of this location.

Cap Alright is situated below the lighthouse in Cap-aux-Meules, Canada. The site is defined by its grey cliffs and a rocky seabed. Due to the nature of the local waters, which are considered dangerous, this location is suitable only for advanced snorkellers. Snorkelling should be attempted exclusively on extremely calm days. Water temperatures at this site fluctuate significantly throughout the year, ranging from a low of -1C in February and March to a high of 19C in August. Access to the water is via the shore.

Pointe-Basse Harbour Rocks in Cap-aux-Meules offers a rugged shore entry near a traditional fishing wharf. The site features a combination of natural rock formations and a breakwater, creating a distinct underwater environment. Divers should expect moderate currents and be aware of boat traffic and surf conditions. Water temperatures are cool, ranging from -1C to 19C throughout the year, with August typically being the warmest month. The site is suitable for intermediate divers, and parking is available for convenience. Snorkelling is also possible at this location, which provides a view of the local cold-water ecosystem.

Dune du Sud, located on Havre-aux-Maisons Island near Cap-aux-Meules, offers accessible sea caves carved into red rock formations. This site is suitable for beginners, with depths ranging from 1 to 5 metres and an average depth of 3 metres. Snorkellers can access the caves directly from the shore. Conditions vary, with visibility typically between 3 and 10 metres and mild currents. Water temperatures are cold, fluctuating between -1C and 19C throughout the year, and the site is noted as being cold for swimming even in September. Hazards include surf and sharp rock formations. Facilities at the site include parking and toilets.