Eureka

Bonnie appears in Pokémon the Series: XY as a traveling companion for Ash alongside Serena and her brother Clemont. She and Clemont first met Ash in Kalos, Where Dreams and Adventures Begin!, but they officially began traveling with him in A Battle of Aerial Mobility!. She also reappeared in Pokémon Journeys: The Series for a two-part episode set in Kalos.

(Source: Bulbapedia)