United States Coast Guard Commemorative Coin Act of 2019 This bill directs the Department of the Treasury to mint and issue in commemoration of the U.S. Coast Guard (1) $5 gold coins, (2) $1 silver coins, and (3) half-dollar clad coins. The design of such coins shall be emblematic of the traditions, history, and heritage of the Coast Guard and its role in securing the United States since 1790. The issuance of such coins is restricted to the one-year period beginning on January 1, 2020. The bill prescribes the sale price of the coins and coin surcharges. Surcharges shall be paid by Treasury to the National Coast Guard Museum Association to help finance the design, construction, operations, and maintenance of the museum.