West off the coast of Los Angeles, the snorkeling off Catalina Island is popular for its diverse marine life among the rock reefs and kelp forests. During Catalina snorkeling, you may encounter bright orange Garibaldi fish, eels, octopus, sea stars, anemones and sea slugs. One thing to keep in mind is that the water temperatures are usually quite cold for most visitors, so you may want to rent a thin wet suit.
There are several popular snorkeling dive sites close to the main port town of Avalon. Right in Avalon, most beginner and less adventurous snorkelers will dive right at Casino Point Underwater Park (aka Casino Point State Marine Reserve). There are stairs right down into the water and the swimming zone is roped off from the boat traffic. The best snorkeling on Catalina is Lovers Cove Marine Reserve, which is located just south of Avalon along the coast. Lover's Cove is known to have an incredibly high density of marine life for the cool west coast waters. It is accessible from the Pebble Beach access stairs. It is also possible to rent a small boat in Avalon and head over to Lovers Cove. Since there is plenty of boat traffic near by in the Avalon port, it is wise to consider using a diver-down flag marker. Another good snorkeling destination is at Toyon Bay. There is a long pier that makes a good artificial reef structure around which to observe marine life, and there are rock reefs on the northern end of the bay. Toyon Bay is known for good water clarity and plentiful marine life.
To reach the snorkeling on Catalina Island from the mainland (22 miles), there are several daily ferries available from both Newport and Long Beach (80 minutes). It is recommended to use one of the first ferries of the day in order to get to the dive sites before the afternoon winds kick up the surf.
Overall, Santa Catalina Island is the 3rd most popular snorkel dive spot of all 11 snorkeling dives in California.