Poni Breaker Coast first appeared in Showdown on Poni Island!, where Ash traveled through it to find Hapu at the Ruins of Hope, only to encounter her and her Mudsdale, which had gone out of control and was running around wildly. Ash noticed something on Mudsdale's foot and had Pikachu use Iron Tail to remove it, revealing that Mudsdale had stepped on a Corsola branch. Hapu felt dejected for having not realized what had been wrong with her Pokémon and asked Ash if she could do something for him in return. Ash, upon noticing Hapu's Z-Ring, asked if he could battle her, but she refused.
The area reappeared in Run, Heroes, Run!, where Ash and Kiawe raced through it to see which of them could get to battle Tapu Fini first. However, their race ended in a tie, so they decided to leave the choice up to Tapu Fini itself.
In A Grand Debut!, Ash and Hapu had their grand trial battle at a battlefield located next to the coast, which revealed itself during low tide. To everyone's surprise, Ash chose to use his Pikachu against Hapu's Mudsdale, despite the obvious type disadvantage. In addition, Mudsdale's Stamina kept activating with each hit Pikachu landed on it, boosting its Defense. However, despite the odds being against him, Ash eventually came up with a strategy of splashing water onto Mudsdale, imitating the move Soak and thus making Mudsdale vulnerable to Pikachu's Electric attacks and allowing him to finish it off with Gigavolt Havoc, making Ash the winner of the grand trial. Afterwards, Hapu presented Ash with a box full of type-specific Z-Crystals and allowed him to choose one of them as his prize. Ash let Pikachu make the choice, and he picked the Steelium Z.