This medal honors the US Submarine Veterans of World War II. This group disbanded in 2012 due to the decreasing number of surviving members. This was a congressionally chartered veterans organization https://en.wikipedia.org/wiki/United_States_Submarine_Veterans_of_World_War_II
This medal was struck by the Hawaii Pacific Mint. Date struck and mintage is unknown. COA provides evidence it was struck by the Hawaii Pacific Mint for a Hawaii-based reseller (Dolphin Medallions).