Safety · Destination Guide
Kelp forests, giant black sea bass, and island time just offshore from Los Angeles
Updated Nov 21, 2025 • 10 sources
Catalina combines remote island logistics with relatively easy access, so it is important to take both diving and topside safety seriously. Cold water, kelp, and variable currents require appropriate training and equipment, while the island’s interior and offshore position make medical evacuations more complex than on the mainland. At the same time, Catalina’s marine and terrestrial ecosystems are heavily protected, with multiple marine protected areas and Conservancy managed wildlands that depend on visitors following leave no trace and no take rules.
Treat Catalina as serious cold water diving. Choose exposure protection based on season, with 7 mm wetsuits, hoods, and gloves or drysuits for winter and spring. Practice kelp skills before entering thick forests, including how to back out calmly and how to cut away entanglements. Always dive with a buddy and carry an SMB, whistle, and cutting tool. Pay attention to surge and currents, especially at offshore banks and backside walls, and plan dives within your certification and comfort zone. When in doubt, dive with local guides who know how wind, swell, and tidal patterns impact specific sites. Check weather forecasts and be ready for ferry or boat cancellations during winter storms.
Catalina Island Health operates the island’s only hospital in Avalon, providing emergency and inpatient care for residents and visitors. For diving accidents, the USC Catalina Hyperbaric Chamber at Big Fisherman Cove is one of the few US chambers dedicated to dive emergencies, operating in coordination with local EMS and the Coast Guard. In a dive emergency, activate local EMS via 911 first, then contact Divers Alert Network’s emergency hotline at +1-919-684-9111 for additional guidance and coordination. Evacuations to mainland hospitals by helicopter or boat may be required for serious injuries.
Cold Water and Thermoclines
Even in summer, Catalina’s water is cool compared with tropical destinations. Winter and spring temperatures around 14°C to 16°C can cause hypothermia if you are underdressed or stay in too long. Plan for 5-7 mm wetsuits with hoods and gloves, or drysuits if you are experienced, and always exit before you are shivering uncontrollably.
Kelp Entanglement and Surge
Kelp is beautiful but can trap hoses, fins, or snorkels. Practice calm, deliberate movements, avoid spinning, and never yank hard on stalks. Carry a small cutting tool, keep your octopus and gauges streamlined, and always surface slowly through kelp, parting it with your hands.
Boat Traffic and Mooring Fields
Avalon, Two Harbors, and many coves are busy with ferries, shore boats, and private yachts. Stay inside designated swim zones, tow a dive flag float when freediving or snorkeling outside parks, and deploy an SMB when surfacing away from moored boats. Never assume skippers can see you.
Strong Currents at Offshore Banks
Advanced sites like Farnsworth Bank and some backside reefs can have strong currents, downwellings, and depths beyond recreational limits. Only dive them with reputable charters, appropriate training, and redundant signaling gear, and be prepared to abort if conditions are not ideal.
Catalina’s waters include several State Marine Conservation Areas, such as Lovers Cove and Casino Point near Avalon and Blue Cavern and Farnsworth Bank offshore. These zones restrict or prohibit the take of living marine resources, so divers, freedivers, and snorkelers must not spear fish, collect invertebrates, or disturb habitats inside their boundaries. On land, the Catalina Island Conservancy manages most of the island’s interior, requiring hiking permits and sometimes road permits to reduce erosion and wildlife disturbance. Follow leave no trace principles, stay on established trails, pack out all trash, avoid feeding wildlife or fish (even where tours allow it), and use reef safe sunscreen to minimize chemical impacts on nearshore ecosystems.
Do Not Do This
Avoid entering when cold water and thermoclines. Confirm local briefings before committing.
| Contact | Role | Phone | Availability |
|---|---|---|---|
| Emergency Services (United States) | Police, fire, and ambulance dispatch for Catalina Island | 911 | 24/7 |
| Catalina Island Health Hospital | Island hospital and emergency department in Avalon | +1-310-510-0700 | 24/7 for emergencies; routine services during posted hours |
| USC Catalina Hyperbaric Chamber | Emergency recompression facility for diving accidents at Big Fisherman Cove | +1-310-510-4020 | 24/7 on-call for dive emergencies via coordination with local EMS and Coast Guard |
| Avalon Harbor Department | Harbor Patrol, mooring assignments, and on-water emergency response near Avalon | +1-310-510-0535 | 24/7 via VHF and phone during boating season |
| LA County Sheriff Avalon Station | Law enforcement for Avalon, Catalina Island, and surrounding waters | +1-310-510-0174 | 24/7 |
| Divers Alert Network (DAN) Emergency Hotline | Global dive emergency medical consultation and evacuation coordination | +1-919-684-9111 | 24/7 for dive and travel medical emergencies worldwide |