The possession of one Mega Ring is offered to the player and each of his or her friends, who have to pick the most deserving out of their group. The selection is quickly whittled down to two people: the player and Serena or Calem (depending on the gender of the player). Upon defeating their rival, the player must obtain the Rumble Badge at the Shalour Gym and then go to the top of the Tower of Mastery to receive the ring from Korrina.
After the player has beaten their rival in Kiloude City, Professor Sycamore will upgrade their Mega Ring at the Anistar Sundial by having the player touch the sundial. Once upgraded, the player can then find hidden Mega Stones around Kalos from 8:00 PM to 9:00 PM.
X was given a Mega Ring with a Key Stone inside from Gurkinn as a child. With it, he can Mega Evolve his Li'l Kanga, Salamè, Élec, Garma, and Rute, into MegaKangaskhan, Mega Charizard X, Mega Manectric, Mega Gengar, and Mega Pinsir, respectively.
In Pinsir Glares, Y was made a Mega Evolution successor by Gurkinn and given a Mega Ring outfitted with the Key Stone from Gurkinn's Mega Glove. With it, she can Mega Evolve her Solsol into Mega Absol.