Underwater diving on Guam

Underwater diving encompasses a variety of economically and culturally significant forms of diving on the U.S. island territory of Guam. Scuba diving tourism is a significant component of the island's tourist activity, in particular for visitors from Japan and South Korea. Recreational diving by Guam residents has a lesser but still substantial economic impact. Marine biologists have raised concerns about the effect of diving upon the health of some of Guam's reefs. Recreational dive sites on Guam include submerged shipwrecks, such as the double wrecks of SMS Cormoran and Tokai Maru, and natural features, such as Blue Hole.

Freedive spearfishing is a culturally and economically important activity for Guam residents, with a history extending to the pre-Spanish CHamoru people. Guam is well represented in local and regional spearfishing competitions. Scuba spearfishing was banned by law in March 2020, after over ten years of resistance from local fishing groups.