Isthmus Reef
Protected Area
Cat Harbor (Catalina Island) State Marine Conservation Area
Why dive here
Isthmus Reef is a reef dive in California, United States. Water ranges 14-21°C, warmest July, August, September.
Isthmus Reef, right off Catalina, is a mellow introduction to California diving. It’s shallow, capping out around 16 meters, which makes it perfect for knocking off some rust or getting comfortable with temperate water. We’ve always found it a solid spot for spotting a leopard shark tucked into the kelp, and the schooling opaleye can be pretty mesmerising as they swirl around the giant bladder kelp. Visibility can be hit or miss, typical for SoCal, but when it's good, it’s a lovely, easy dive.
Typical Isthmus Reef Dive Profile
Illustrative profile based on site depth and type. Actual dive profiles vary - always follow your dive computer and training.
Safety Notes
Always perform a 3-minute safety stop at 5m before surfacing.
Nearest Dive Centres to Isthmus Reef
Dive shops near Isthmus Reef
Catalina Scuba
Kelp Forest
Catalina Divers Supply & Snorkeling
Ron Moore's Dive Catalina
Pacific Wilderness, Inc.
Dive N' Surf
Reviews for Isthmus Reef
Conditions
Ocean conditions, forecast and tides for Isthmus Reef
Isthmus Reef Ocean Conditions
Monthly averages for Isthmus Reef, sourced from NOAA NDBC buoy data - nearest station: Topanga Nearshore, CA (103) (221km away)
October Averages
Sea Temperature
19°C
66°F · Range: 14–23.7°C
Air Temperature
18°C
65°F
Wave Height
0.6m
13.8s period
Based on 4 years of monitoring data · Data sources: NOAA NDBC buoy data
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