Some trials in Pokémon Ultra Sun and Pokémon Ultra Moon play out in different ways than they did in Pokémon Sun and Pokémon Moon. The island challenge is a ritual passed down in the Alola region. Its intention is to help children grow into full-fledged Pokémon Trainers. To complete the island challenge, you must face trials on each of four islands. The trials are hosted by the captains found on each island. The content of the trials can vary from running around the area to trying to solve puzzles.
At the end of each trial, you’ll face a powerful Pokémon known as a totem, such as the Alolan Marowak in the above screenshot. If you defeat it, you’ll complete the trial. The final trial of each island is the grand trial, where you face off in battle against the leader of that island—the island kahuna! There’s even a new trial with Mina, one of the captains who serve as guides for these trials.