Sosuke

Sōsuke is intelligent, smart, loyal, cute and heroic. He is willing to protect his friends (including Ponyo, starting from when she washes up on the shore near the house, stuck in a glass jar), even if doing so gets him in trouble with his mother or Ponyo's father (whom they hate). He is interested in the sea, especially since his father is the captain of a ship. He also knows that Kōichi does his best for the family, as seen when Lisa gets angry at Kōichi and chides him for abandoning her family on a cliff.

Sōsuke is a 5-year-old boy who wears a sunshine yellow t-shirt and chocolate brown shorts, and white slip-on shoes. His hair is walnut brown with his hair shaven underneath. Also, he sometimes wears a sailor hat and binoculars.