Oil Rigs Elly-Ellen are two offshore oil platforms located 13 kilometres from shore near Avalon. These artificial reef structures feature a complex network of legs and crossbeams reaching depths of 12 to 40 metres, with an average depth of 18 metres. This advanced site requires boat access and presents significant challenges, including strong currents, heavy surge, and an overhead environment. Visibility is highly variable, ranging from 3 to 30 metres. Water temperatures remain between 14 and 17 degrees Celsius, with thermoclines common at depth. Divers must manage risks associated with deep diving, nitrogen narcosis, and frequent vessel traffic. A drysuit or thick wetsuit is essential for these conditions.

Oil Rig Edith is a decommissioned structure located 13 kilometres offshore from Avalon, serving as an artificial reef. The site features a complex superstructure providing hard substrate for marine growth between 30 and 40 metres. Divers typically experience visibility ranging from 10 to 15 metres, with water temperatures between 14 and 17C. Due to the significant depth, moderate currents, and potential thermoclines, this site is strictly for advanced divers. Access is exclusively by boat, and divers must be prepared for active boat traffic during ascent. Careful gas planning and the use of a surface marker buoy are essential for safety at this location.

UB-88 is a First World War German U-boat resting upright on the seafloor at a depth of 61 metres. This technical dive site requires trimix or rebreather certification due to the significant depth and mandatory decompression obligations. The wreck serves as an artificial reef, though divers must manage entanglement risks when exploring the overhead environment. Conditions include mild currents and visibility ranging from 5 to 10 metres. Water temperatures are cool, fluctuating between 13 and 16 degrees Celsius, making a drysuit or high-grade wetsuit essential. Access is strictly by boat, and divers should carry a surface marker buoy and reel for the ascent due to constant local boat traffic.

Long Beach Breakwater is an artificial reef located near Two Harbors, Santa Catalina Island. This site is suitable for beginners, offering a manageable depth range of 8 to 12 metres with an average of 9 metres. Divers access the reef from the shore, encountering mild currents and visibility ranging from 5 to 15 metres. Due to variable visibility and active boat traffic, divers should exercise caution and tow a surface marker buoy throughout the 45-minute dive. Water temperatures fluctuate between 15 and 20 degrees Celsius, making a wetsuit necessary for comfort. Always check local conditions and facility availability before planning your dive.

Olympic II is a wreck dive located off the coast of Two Harbors, Santa Catalina Island. This site is strictly for advanced divers due to the depth, which averages 30 metres, and the presence of moderate currents. Access is exclusively by boat, as the wreck lies approximately 5633 metres from the shore. Divers should be aware of potential hazards including boat traffic, entanglement risks, and strong currents. Visibility at this location is variable, ranging from 10 to 80 metres. Water temperatures fluctuate throughout the year, reaching a maximum of 18C in late summer and dropping to 14C during the winter months.

Radio Tower is an artificial reef located off Two Harbors, Santa Catalina Island. This site sits at depths between 26 and 34 metres, with an average depth of 30 metres, making it suitable only for advanced divers. Access is by boat only. Visibility typically ranges from 5 to 10 metres, and currents are variable. Divers must exercise caution regarding nitrogen narcosis and decompression requirements due to the depth. The artificial structure presents potential entanglement hazards, necessitating precise buoyancy control. Always confirm current conditions with your skipper before entry and carry an SMB to manage boat traffic and ascent safety.

Cabrillo Beach in Two Harbors offers a shallow, accessible shore dive suitable for beginners. The site features a mix of reef, kelp forest, seagrass, and artificial reef habitats. Divers can expect depths ranging from 3 to 9 metres, with an average of 6 metres. Conditions include mild currents and visibility between 3 and 10 metres. Water temperatures fluctuate between 15C and 20C, with potential for rapid, significant cooling. The site is equipped with parking, toilets, showers, and a rinse station. Night diving is permitted, and typical dives last around 45 minutes. Hazards include low visibility, sharks, sharp coral, strong currents, and surf.

Little Corona del Mar is a coastal cove featuring rocky outcroppings, reefs, and kelp forests. Accessible via a paved path leading to the sand, the site is suitable for beginners and offers both diving and snorkelling opportunities. Depths range from 5 to 10 metres, with an average of 6 metres. Divers and snorkellers should be aware of potential hazards including boat traffic, rip currents, surf, surge, and sharp rock formations. Visibility typically ranges between 9 and 10 metres, and water temperatures fluctuate between 15C and 20C throughout the year. Facilities at the site include parking, toilets, and showers.