Synopsis
Another addition to the Marine Boy franchise. This time, 65 episodes were produced to extend the 1966 series, and all 78 episodes were sold to the United States. The show's airing pattern in Japan was a bit more complex: initially, only the first 36 of the 78 episodes were broadcast, but later all 78 aired—65 are part of this entry, while 13 belong to the Ganbare! Marine Kid series. Marine now wields an underwater boomerang and a hydrojet, and the mermaid Neptuna/Neptina has become his girlfriend. Some earlier episodes from Ganbare! Marine Kid had their footage partially reused for this series.