To wield Mega Evolution, a player must first obtain the following:
- A Mega Ring
- A Mega Stone
- A Pokémon compatible with the Mega Stone
To obtain a Mega Ring, a Mega Evolved boss Pokémon must be found and defeated by the player. Upon doing so, the player will be given the option to wear the Mega Ring, which is necessary to trigger Mega Evolution.
Mega Stones can be obtained from their corresponding Mega Evolved boss Pokémon. The first defeated Mega Evolved boss Pokémon of each Pokémon species will always drop its Mega Stone, while subsequent boss Pokémon defeats will have a 1/40 chance of dropping the corresponding Mega Stone again.
For example, a player who has not obtained any Mega Stones or a Mega Ring defeats a boss Mega Venusaur. The Venusaur is guaranteed to yield a Mega Ring and a Venusaurite. If the player finds another boss Mega Venusaur, there is a /140 chance that the boss will drop a second Venusaurite for the player upon defeat. If the player later finds a boss Mega Blastoise, the Blastoise will be guaranteed to drop a Blastoisinite because it is the first Mega Blastoise that the player has defeated.
Only certain Pokémon can Mega Evolve. Charizard has two different Mega Evolutions that each require a different Mega Stone.