To evolve Gurdurr into Conkeldurr in Pokémon Scarlet and Violet, you’ll need to trade. See where to find Gurdurr and how to evolve it in The Teal Mask DLC.
Conkeldurr is a special evolution of Gudurr, a fighting-type Pokémon from Unova, and it’s now in Pokémon Scarlet and Violet: The Teal Mask DLC.
You can find Timburr and Gurdurr in the wild in Kitakami, the area unlocked by The Teal Mask DLC. If you don’t have the DLC, you can still get these Pokémon via trade from somebody else who has them.
Finding Timburr and Gurdurr is easy and evolving it is even easier, though you will need a Nintendo Switch Online subscription or an IRL friend to trade with.
