Iliuliuk Reef is a submerged reef system situated at the entrance to Iliuliuk Harbor. This site is accessible only by boat and is suited for advanced divers due to the presence of strong currents. Water temperatures are cold, ranging from 3C to 9C throughout the year. Divers should remain aware of boat traffic in the area. The reef is noted for hosting dense populations of cold-water invertebrates. Snorkelling is possible at this location, which carries a rating of 4 out of 5.

Summer Bay Beach on Unalaska Island provides shore access to the Bering Sea, featuring a mix of reef and kelp forest habitats. Snorkellers can explore depths ranging from 0 to 10 metres, with an average depth of 5 metres. Conditions are variable, with visibility typically between 3 and 10 metres and moderate currents. The site is suited for intermediate snorkellers due to the cold water temperatures, which range from 4 to 9°C throughout the year. Hazards include surf, boat traffic, jellyfish, sea urchins, and strong currents. The area is also known for its sandy beach and tide pools accessible during low tide.

Morris Cove is a remote, rugged site located in the Aleutians, United States. Accessible via a rough 4WD track, this shore-entry location offers a wild snorkeling experience. The site is deep and subject to strong currents and surf, making it suitable only for advanced snorkelers. Water temperatures are very cold, ranging from 4°C to 9°C throughout the year, necessitating specialized cold-water gear such as 7mm wetsuits, hoods, gloves, and boots. The habitat supports a variety of temperate marine life, including various fish, invertebrates, and marine mammals typical of the region. Divers and snorkelers should be aware of hazards including cold water, deep conditions, strong currents, surf, and the presence of sharks.

Humpy Cove is a rocky reef site in the United States that offers a sheltered environment for advanced divers. The site features a rocky shoreline providing structure for intertidal life, anemones, and nudibranchs. Access is via a shore entry. Conditions are characterised by cold water, with temperatures ranging from 4C to 9C throughout the year. Divers should be prepared for potential surf and variable visibility. While the site is suitable for snorkelling, the cold water temperatures require appropriate thermal protection for all in-water activities. The cove is noted for its salmon runs during the late summer months.