Pokémon Legends: Z-A's competitive online mode, Ranked Battles, is introducing a fresh restriction for its 15th season, requiring players to build teams using only Water-type Pokémon. This continues a pattern of themed seasonal shake-ups, following Season 13's ban on legendary and mythical Pokémon and Season 14's Flying-type-only restriction, keeping the ranked format varied for competitive players.

Eligible Water-types are drawn from both the base game's Lumiose Pokédex and the Mega Dimension DLC's Hyperspace Pokédex, including popular picks such as Gyarados, Vaporeon, Blastoise, Greninja, Swampert, Milotic and the legendary Kyogre, with all Pokémon standardised to level 50. Rewards mirror previous seasons, including Fresh Water, Feathers and Mega Stones such as Swampertite and Blazikenite for climbing through the ranks. Season 15 runs from 6 to 27 August, coinciding with the release of Pokémon Pokopia's first DLC expansion, Bubbly Basin, on 5 August.