East of Honolulu, the snorkeling at Ko Olina Lagoons is known for its range of marine life including barracuda, butterflyfish, goatfish, moorish idols, surgeon fish and wrasse. The water depths range from 4 to 5 feet deep.
The four manmade Ko Olina Lagoons are interconnected by a 1.5 mile path stretching from Lagoon #1 to Lagoon #4. The lagoons offer protected year-round snorkeling. Unfortunately, the visibility is usually poor, there are no reefs to explore and the lagoons can become very crowded.
To reach the Ko Olina Lagoons snorkeling from Honolulu, head west on H-1 to Highway 93. Use the exit for Ko Olina onto Ali'i Nui Drive. There is a small public parking area at each lagoon, with the largest parking area at Lagoon #4. To reach the best snorkeling on Oahu by air, you will need to fly into Honolulu International Airport (HNL) which is located just on the west side of Honolulu. There are direct flights into Honolulu from the US, Australia, New Zealand, American Samoa, Tahiti, Japan and Fiji. In addition, there are inter-island flights to all the main Hawaiian Islands. There is good snorkeling on Oahu year-round. But, the conditions very around the island depending upon time of year due to winds and currents. The north shore snorkeling dives are best from June through September and are usually closed out the rest of the year due to high surf. The south shore dive sites are best from November through May. The main exception is Hanauma Bay, which tends to be good year-round since it is very protected.
Overall, Ko Olina Lagoons is the 4th most popular snorkel dive spot of all 23 snorkeling dives in Oahu.