Maren is a character from The Power of One. Her English voice actress is Tara Jayne and her Japanese voice actress is Kotono Mitsuishi.

In the movie, she gave Ash, Misty, Tracey and their Pokémon a ride around the Orange Islands; however, a storm blew them off-course, and they were forced to land at Shamouti Island.

While on the island, Maren was surprised to see her old friend Carol on the island. With her, she learned all about the Legendary Pokémon and the collecting of the spheres. She volunteered to help Ash on his journey to find them. Unfortunately, her boat crashed and sustained serious damage on one of the islands. She was last seen in the credits of the movie, leaving Shamouti Island with Ash and the others.

(Source: Bulbapedia)