Chemical analysis of a marine-derived Vibrio sp. (Q-459) isolated from a depth of 10 m near Okinawa prefecture Japan, yielded a new cyclic acyldepsipeptide, kailuin F (1) together with the known kailuins B (3) and E (6). The structure of 1 was elucidated based on spectroscopic methods including UV, HR-ESIMS, chemical derivatizations and 1D, 2D NMR data. Kailuin B (3) exhibited a strong antimicroalgal activity against the dinoflagellate Prorocentrum micans.