Charlotte Amalie Harbor Seaplane Base (IATA: SPB, FAA LID: VI22), also known as St. Thomas Seaplane Base, is located in the harbor by Charlotte Amalie, Saint Thomas, U.S. Virgin Islands.

This private-use airport is owned by the Virgin Islands Port Authority.

[2] Charlotte Amalie Harbor Seaplane Base covers an area of 3 acres (12,000 m2) and has two seaplane landing areas:[1] Historically, Virgin Islands Seaplane Shuttle[3][4][5][6] operated scheduled passenger service during the 1980s from the Charlotte Amalie seaplane base with Grumman Mallard aircraft.

During the 1970s, Antilles Air Boats[7][8][9][10][11][12] operated several different types of seaplanes in scheduled passenger service from the harbor as well including the Consolidated PBY Catalina (Super Catalina version), Grumman Goose, Grumman Mallard, Short Sandringham S-25 and Vought Sikorsky VS-44.

The terminal was named the Charles F. Blair, Jr.[13][14][15][16][17] terminal in honor of Charles F. Blair, Jr., an aviation pioneer and the founder of the seaplane airline, Antilles Air Boats.