How do you level up Altaria?

To level up Altaria in Pokémon games, you need to gain experience points (XP) by battling and defeating other Pokémon or by participating in various activities such as raids or completing missions. Altaria evolves from Swablu starting at level 35, so you can also use experience candies or rare candies to speed up the leveling process. Additionally, using a Lucky Egg can increase the XP gained during battles. Focus on using Altaria in battles where it can gain the most experience against opponents it has an advantage over.