Another installment in the Marine Boy series. This time, 65 episodes were added to the 1966 series, and the entire 78-episode run was sold in the United States. In Japan, the show's broadcast history was slightly more difficult, with just the first 36 episodes of the 78 televised at first, but eventually all 78 were shown, 65 of which are included in this entry and 13 in the Ganbare! The Marine Kid series Marine now possesses an underwater boomerang and a hydrojet, and Neptuna/Neptina, a mermaid, has become his lover. Previously aired Ganbare episodes! Marine Kid's footage was reused in part for this series.