If held by a Swampert, allows it to Mega Evolve into Mega Swampert if its Trainer has a Key Stone. Each Trainer can only Mega Evolve one Pokémon per battle.
Unaffected by item negating effects (such as Embargo and Klutz). Item manipulating effects (such as Trick and Fling) cannot give Swampert a Swampertite or remove a Swampertite from Swampert.
Outside of battle
If held by a Swampert, allows it to Mega Evolve into Mega Swampert when it performs a Spectacular Talent during a Pokémon Contest Spectacular while its Trainer has a Key Stone. Swampert will remain a Mega Swampert until the Talent Round ends.
The player can obtain the Swampertite by completing Mission Card 18.
The Swampertite was also available as a prize during the Mega Swampert Competitive Stage. This Competitive Stage ran on both the Nintendo 3DS and Mobile versions from January 5 to 12, 2016 and May 10 to 17, 2016. It ran on the Pokémon Shuffle Mobile from May 10 to 17, 2016.
The Swampertite enables the following Mega Evolution: