North Coronado features a diverse underwater landscape comprising reef, wall, and artificial reef structures. Located off the Coronado Islands, this site offers depths ranging from 3 to 24 metres with an average of 18 metres. Visibility typically spans 10 to 30 metres. Divers must access the site by boat and should be prepared for moderate currents, surge, and thermoclines that can significantly lower water temperatures at depth. Due to these conditions and potential boat traffic, the site is suited for intermediate divers. Species recorded around this area include California sea lions, northern elephant seals, Garibaldi, and various sea stars.

The Keyhole, also known as McDonald's, is a reef and drift site located at the southern tip of North Coronado Island. The site is defined by a natural archway and a channel, which provides a distinct topography for divers and snorkelers. Depths range from 3 to 24 metres, with an average of 18 metres. Access is by boat only, and the site is suited for intermediate divers due to moderate currents and potential surge. Visibility typically fluctuates between 9 and 24 metres. Water temperatures are cool, ranging from 14 to 17 degrees Celsius, with occasional thermoclines reaching the low 10s at depth.

Middle Grounds is a rocky reef situated between the North and South islands of the Coronado Islands. This site features depths ranging from 6 to 24 metres, with an average depth of 15 metres. Divers and snorkellers experience visibility between 9 and 30 metres, though conditions vary. The site is accessible only by boat and is suitable for beginners. Water temperatures typically range from 14 to 17C, with occasional thermoclines dropping to 10C at depth. Hazards include boat traffic, jellyfish, sea urchins, strong currents, and surge. Guided tours, boat charters, and equipment rentals are available locally.

Middle Rock is a reef and kelp forest site located off the Coronado Islands. Divers typically explore depths between 12 and 19 metres, with visibility ranging from 10 to 30 metres. The site features moderate currents and occasional thermoclines, requiring careful monitoring of depth gauges. Access is by boat only, and divers should remain alert for boat traffic during surface intervals and ascents. Species recorded around this area include California sea lions, northern elephant seals, harbour seals, Garibaldi, and various wrasses. Due to the current and surge, this site is best suited for those comfortable with changing conditions, and the use of a delayed surface marker buoy is recommended.

Moonlight Cove is a protected reef located on the northeast side of Central Coronado Island. This site is accessible only by boat and offers depths ranging from 5 to 15 metres. It is suitable for beginners, though divers should be aware of potential hazards including surge, strong currents, and thermoclines that can cause water temperatures to drop below the average range of 15 to 19 degrees Celsius. Visibility at the site varies between 9 and 25 metres. Due to the presence of jellyfish, appropriate exposure protection is recommended. The site provides a sheltered environment for those looking to explore the local reef topography.

Islas Coronado offers diverse underwater topography including reefs, walls, and kelp forests, alongside artificial reef structures. Located over 11 kilometres from the shore, this site requires boat access. Divers experience depths ranging from 10 to 82 metres, with an average depth of 15 metres. Conditions vary, with visibility typically between 9 and 25 metres and mild currents. Water temperatures fluctuate between 11C and 16C, and thermoclines can cause significant drops in temperature at depth. Hazards include cold water, jellyfish, sea urchins, strong currents, and surge. The site provides multiple locations suitable for various skill levels, with typical dives lasting around 45 minutes.

Toilet Bowl Grotto is a unique geological formation at the Coronado Islands, Mexico, characterised by a rocky grotto where surge creates a swirling flushing effect. This advanced site requires boat access and is suitable only for experienced divers due to strong currents and significant surge. Depths range from 6 to 24 metres, with an average of 20 metres. Visibility varies between 9 and 30 metres, and water temperatures typically range from 14 to 17C, though thermoclines can cause temperatures to drop into the low 10s C at depth. Species recorded around this area include California sea lions, northern elephant seals, Garibaldi, and various wrasses and sea stars.

Middle Coronado Island offers a diverse underwater environment featuring a mix of reef, wall, and kelp forest structures. Divers can explore depths ranging from 13 to 19 metres, with an average depth of 16 metres. The site is accessible only by boat and provides visibility up to 30 metres. While currents are generally mild, divers should remain prepared for surge, swell, and shifting currents near the walls. Due to boat traffic in the area, the use of a surface marker buoy is recommended upon ascent. Water temperatures typically range between 15 and 18 degrees Celsius, though thermoclines can occasionally cause temperatures to drop to approximately 10 to 11 degrees Celsius at depth.