Although Mewtwo was absent from Pokémon Sword and Shield at launch, a limited-time event a few months after its release introduced an uncatchable, extremely difficult Dynamax Mewtwo to the game. Luckily, with the addition of the game's The Crown Tundra expansion, finding and catching Mewtwo in Pokémon Sword and Shield is now possible at any time.
During a single weekend in February 2020, players were able to randomly encounter Mewtwo in Max Raid Dens in the Wild Area. The Legendary Pokémon was truly powerful, as it was level 100, fully EV trained (meaning its stats were maxed out), and could use six different moves, as opposed to the usual four. This Max Raid event could theoretically come back someday, in which case players will want to approach the returning hardest battle in Pokémon with real human teammates and ultra-powerful Pokémon, such as Necrozma, Zacian, or Dracovish. Game Freak has not repeated any events since Sword and Shield's release, however, so this is rather unlikely.
How To Get Mewtwo In Pokémon Sword & Shield: The Crown Tundra
While previous games have seen Mewtwo catchable like any other static-encounter Legendary Pokémon in the wild, getting Mewtwo in Sword and Shield requires players to delve into a Dynamax Adventure. This means they'll have to own the Crown Tundra expansion, purchasable only through the Pokémon Sword Expansion Pass or Pokémon Shield Expansion Pass. Once in the titular Crown Tundra area, players will have to make their way to the Max Lair to get started.
Dynamax Adventures put players in three Max Raid Battles against regular Pokémon, then one against a Dynamaxed Legendary. At the start of each run, players are shown the type of the Legendary they'll face at the end. If it's a pure-Psychic type, it can only be Mewtwo, Uxie, Mesprit, Azelf, Cresselia, or Necrozma, but there are 47 total possible Legendaries to encounter, so the chances of getting a Mewtwo on the first try are low. Players will simply have to keep beating Dynamax Adventures until they encounter Pokémon Sword and Shield's Mewtwo.
Luckily, once Mewtwo is found, a few factors ensure it's fairly easy to catch. First, any Pokémon defeated in a Dynamax Adventure battle can be caught automatically, so there's no chance of it running away, unlike regular Max Raid Battles. Players just need to choose Mewtwo as the Pokémon they're keeping at the end of the Dynamax Adventure run. Second, if players do fail to take down the monster, they'll be able to record its location, letting them guarantee an encounter with Mewtwo in Pokémon Sword and Shield on a subsequent run. Unfortunately, only one Mewtwo can be caught per save file; further encounters with the Pokémon won't let players capture it.
Pokémon Sword and Shield are available now on Nintendo Switch.