Marine Boy is an extremely intelligent, strong and athletic boy of perhaps 13 to 15 years of age. He is a martial artist (episode 1, 2, 8, 16), football player (ep. 17), and an accomplished pilot (ep. 10) whose talents are further enhanced by the inventions of his father, Dr. Mariner. He has a great affinity with sea life, most particularly with a white dolphin he calls Splasher who Marine Boy occasionally seems able to communicate with quite clearly (ep. 11, 12, 17, 28). (MB also wears a ring with a dolphin-calling whistle in it (ep. 2, 4, 16).) It is perhaps because of his skills along with his avid insistence to get involved with trouble that his father, along with Professor Fumble, invented for him the red wetsuit which protects and equips Marine Boy, allowing for him to use his talents to perform dangerous duty. With his headstrong personality, he hardly seems able to avoid it.