Sinistea is a Generation XIII Pokémon that can also be found in Pokémon Scarlet and Violet. It's not a version exclusive Pokémon itself, but Sinistea's crafting material drop, Sinistea Chips, are used exclusively in Pokémon Violet to trade for the Malicious Armor to evolve Charcadet into Ceruledge. Here is where you can find and catch Sinistea in Pokémon Scarlet and Violet.
Where to catch Sinistea in Pokémon Scarlet & Violet
Sinistea can be found in two areas of Pokémon Scarlet and Violet: Zapapico and Alfornada. Alfornada is a late game area, so we definitely recommend looking around Zapapico first if you are looking to get this Pokémon early. That's where we found ours.
If you want the Pokémon for yourself, catch it. If you are looking for Sinistea for its crafting drop, you may want to use Let's Go mode to defeat Sinistea instead, as this will guarantee crafting material drops with each Pokémon defeated. You'll need 10 Sinistea Chips to trade for the Malicious Armor in Pokémon Violet. Give that Malicious Armor to Charcadet and he will immediately evolve in Ceruledge.
Looking for information on Charcadet or Ceruledge's nature or other Scarlet & Violet Pokémon? Check out Best Nature for Charcadet, Armarouge, & Ceruledge in Pokémon Scarlet & Violet and Best Nature for Tatsugiri in Pokémon Scarlet & Violet here at Pro Game Guides.