North of Tumon the northwest coast of Guam, the snorkeling at Double Reef is considered by many as the best on the island. There is a fringing inner reef and a barrier outer reef that both have healthy dense coral growth. It does take about an hour to hike down to Double Reef Beach, but the snorkeling over the two sets of reefs is very scenic. Alternately, it can be accessed by boat.
To reach the Guam snorkeling by air, fly into the Antonio B. Won Pat International Airport (GUM) which is located in the middle of the island. The Double Reef snorkeling dive site is located north of Tumon and just offshore of Pugua Point.
While the dry season is typically January to June, the best snorkeling on Guam is during the months of May through August. The highest water clarity can be found if there is an incoming tide during the morning. While snorkeling in Guam, keep an eye out for green sea turtles, hawksbill turtles and dozens of species of sharks. Overall, there are over 700 species of reef fish and over 300 species of coral on the fringing reefs. Most snorkelers stay within the fringing reef since there is usually a strong current just beyond the reef. There are a couple lesser well-known snorkeling dive sites off the east coast of Guam, which should only be attempted during the local summer months and then only with extreme care.
Overall, Double Reef is the 14th most popular snorkel dive spot of all 17 snorkeling dives in Guam.