USS Dapdap (YFB-684) was a United States Navy working launch in service from 1908 to 1942.
Dapdap (YFB-684), a working launch, was attached to the Naval Station, Cavite, Philippine Islands, or the 16th Naval District from 1908 to 1942.
Dapdap was lost, 2 January 1942, to Japanese forces during the conquest of Luzon Island.
She was stricken from the Navy List on 24 July 1942.