USS Humboldt, a 1,766-ton Barnegat class small seaplane tender, was built at the Boston Navy Yard, Massachusetts, and was commissioned in October 1941. Following a prolonged shakedown period, she departed Norfolk in May 1942 and commenced tending seaplanes at Recife, Brazil, in August. She served at various points along the Brazilian coast until July 1943, when she returned to the Boston Navy Yard for a short repair period

From August 1943 to early 1945, Humboldt served in the North Atlantic theater, including Newfoundland, Iceland, the United Kingdom, and French North Africa. After a repair period at Norfolk, she returned to Brazil in April 1945 for another two months of South Atlantic duty. She arrived at the Philadelphia Navy Yard in July 1945 and commenced conversion to a press ship for the invasion of Japan. As such, she was reclassified AG-121 on 30 July 1945 but reverted to AVP-21 on 10 September 1945 after the conversion was cancelled. Humboldt was decommissioned in March 1947 and placed in reserve.

In January 1949 Humboldt was loaned to the Coast Guard and served out of Boston, Massachusetts, primarily on weather duty, as the cutter Humboldt (WAVP-372, later WHEC-372). She was decommissioned by the Coast Guard in September 1969 and sold for scrapping in May 1970.