Speak to the shopkeeper closest to door after receiving mega stones
Mega Pokémon
Mega Stone
Location
Mega Houndoom R
Houndoominite R
Adoption Center
Mega Sableye R
Sablenite R
Adoption Center
Mega Garchomp R
Garchompite R
Adoption Center
Mega Arcanine R
Arcanite R
Adoption Center
Mega Skarmory R
Skarmorite R
Adoption Center
Mega Machamp R
Machampite R
Adoption Center
Mega Beedrill R
Beedrillite R
Adoption Center
Mega Tyranitar R
Tyranitarite R
Adoption Center
Mega Alakazam R
Alakazite R
Adoption Center
Mega Scrafty
Scraftite
Adoption Center
Mega Frosslass
Frosslassite
Adoption Center
Mega Ribombee
Ribombite
Adoption Center
Mega Ursaluna
Ursalunite
Adoption Center
Mega Mawile R
Mawilite R
Adoption Center
Mega Wigglytuff Y
Wigglytuffite Y
Adoption Center
Mega Wigglytuff X
Wigglytuffite X
Adoption Center
Mega Tinkaton
Tinkatite
Adoption Center
Mega Hydreigon R
Hydreigonite R
Adoption Center
Mega Infernape R
Infernapite R
Adoption Center
Mega Torterra R
Torterranite R
Adoption Center
Mega Empoleon R
Empoleonite R
Adoption Center
Mega Clefable R
Clefablite R
Adoption Center
Mega Rapidash
Rapidashite
Adoption Center
Mega Rapidash G
Rapidashite G
Adoption Center
Mega Lucario Y
Lucarionite Y
Adoption Center
Mega Gyaradeath X
Gyaradeathite X
Adoption Center
Mega Gyaradeath Y
Gyaradeathite Y
Adoption Center
Mega Flygon R
Flygonite R
Adoption Center
Mega Tsareena R
Tsareenite R
Adoption Center
Mega Reuniclus R
Reuniclusite R
Adoption Center
Mega Golisopod
Golisopodite
Adoption Center
Mega Toxtricity R
Toxtricityite R
Adoption Center
Mega Arbok
Arbokite
Adoption Center
Mega Popcorm
Popcormite
Adoption Center
Mega Cormoth
Cormothite
Adoption Center
Mega Amphybuzz
Amphybuzzite
Adoption Center
Mega Aegislash R
Aegislashite R
Adoption Center
Mega Oricorio
Oricorionite
Adoption Center
Mega Glalie R
Glalite R
Adoption Center
Mega Frosslass R
Frosslassite R
Adoption Center
Mega Gengar X
Gengarite X
Adoption Center
Mega Venusaur X
Venusaurite X
Adoption Center
Mega Chariard Z
Chariardite Z
Adoption Center
Mega Blastoise X
Blastoisenite X
Adoption Center
Mega Orbeetle
Orbeetite
Adoption Center
Mega Corviknight
Corvinite
Adoption Center
Mega Centiskorch
Centiskite
Adoption Center
Mega Alcremie
Alcremite
Adoption Center
Mega Sandaconda
Sandacondite
Adoption Center
Mega Snorlax
Snorlaxite
Adoption Center
Mega Coalossal
Coalossalite
Adoption Center
Mega Cinderace
Cinderaceite
Adoption Center
Mega Rillaboom
Rillaboomite
Adoption Center
Mega Inteleon
Inteleonite
Adoption Center
Mega Drednaw
Drednawite
Adoption Center
Mega Garbodor
Garbodorite
Adoption Center
Mega Grimmsnarl
Grimmsnarlite
Adoption Center
Mega Hatterene
Hatterenite
Adoption Center
Mega Copperajah
Copperajite
Adoption Center
Mega Toxtricity
Toxtricitite
Adoption Center
Mega Kingambit R
Kingambitite R
Adoption Center
Post-Norman (Gym 5 Defeated)
Mega Pokémon
Mega Stone
Location
Mega Torterra
Torterranite
Top left of the Game Corner, Maniac that loves you. Requires 5 Gym Badges. 3 Mega vs 6 battle.
Mega Infernape
Infernapeite
Mega Empoleon
Empoleonite
Mega Meganium
Meganiumite
Verdanturf Meadow. Requires 5 Gym Badges. Defeat the Aroma Lady.
Mega Feraligatr X
Feraligatrite X
Route 105 on a small beach. Requires 5 Gym Badges. Defeat the Sailor.
Mega Feraligatr Y
Feraligatrite Y
Route 114. Requires 5 Gym Badges. Totem battle!
Mega Typhlosion
Typhlosionite
Top right section of Ashen Woods. Requires 5 Gym Badges. Defeat the Kindler.
Mega Breloom
Breloomite
North of Petalburg Forest (New Area). Requires 5 Gym Badges. Totem battle!
Mega Lanturn
Lanturnite
Mauville City. Quest Reward. Requires 5 Gym Badges. Talk to Wattson and give him an hand!
Mega Sandslash
Sandslashite
South of Route 111, Desert. Requires 5 Gym Badges. Totem battle!
Mega Krookodile
Krookodilenite
Extra zone outside of Mirage Tower, accessible from Sandstrewn Ruins under the Mirage Tower or tunnel in Fossil Manic's House in Route 114. Requires 5 Gym Badges. Defeat the Ruin Maniac.
Post-Winona (Gym 6 Defeated)
By defeating Winona, several Megas can be unlocked
Mega Pokémon
Mega Stone
Location
Mega Nidoking
Nidokingite
Outside Rusturf Tunnel, Route 116. Requires 6 Gym Badges. Exit Rusturf Tunnel from the third entrance, close to the entrance from Verdanturf Town, where the Black Glasses Quest is .Defeat the Ace Trainer. This is a forced Double Battle.
Abandoned Ship, Route 108. Requires 7 Gym Badges. Dive underwater in one of the rooms and collect keys to access hidden rooms. Defeat the Bug Catcher in one of the hidden rooms. Note: Its unique ability only works once per battle, switching doesn't reset the counter.
Mega Haxorus
Haxorusite
Meteor Falls. Requires 7 Gym Badges. Totem battle. Find the trainer guarding the opening to another zone, where the Totem battle lies.