A Trial Captain (Japanese: キャプテンCaptain) is a person who designs and presides over a certain island challenge trial and gives guidance to participating Trainers. All of the Trial Captains have previously completed their own island challenge a few years prior. They retire from their position when they turn 20. Like Gym Leaders, they specialize in certain types of Pokémon. There are usually seven Trial Captains at one period of time to match the seven ordinary trials in the island challenge, although as shown by the Vast Poni Canyon trial, a trial can exist in a functional form without a Captain to preside over it.
Normally, Captains are chosen by the island's Kahuna. However, in special circumstances, they may be chosen by the previous Captain, as was the case when Molayne chose Sophocles to succeed him after retiring.