It is first seen when Sōsuke fills the bucket with water for a place ponyo can stay in. He took Ponyo in the car and offered bread but Ponyo ravenously ate the ham. At Himawari Nursery School, Sōsuke leaves Ponyo under some bushes. Later, Kumiko takes a peek at Ponyo and Ponyo squirts water on Kumiko's new dress. After Ponyo's father, Fujimoto, takes her back, Sōsuke is left only with the bucket and places it on the fence post of his home so Ponyo will know where to return. Later, in the scene where the raging waters are up the house on the hill, Ponyo appears to Sōsuke, holding the bucket. When Ponyo and Sōsuke journey out on their boat, they bring the bucket.
In the end, Ponyo jumps from the bucket to kiss Sōsuke to become human.