USS Legonia II (SP-399) was a United States Navy patrol vessel in commission from 1917 to 1921. Legonia II was built as the private steam yacht Walucia in 1909 by Pusey & Jones at Wilmington, Delaware. She later was renamed Lydonia, then Legonia II. On 6 June 1917, the U.S. Navy purchased her from William B. Hurst of Baltimore, Maryland, for use as a section patrol vessel during World War I. The Navy took delivery of her from Hurst on 9 June 1917, and she was enrolled in the on 12 June 1917. She was commissioned at Baltimore as USS Legonia II (SP-399) on 14 June 1917.