you have to get it in a event and you cant get it in Pokemon leafgreen or firered
Pokemon Emerald: Birth Island Pokemon Sapphire: Trade from Pokemon FireRed, LeafGreen, or Emerald. Pokemon Ruby: Trade from Pokemon FireRed, LeafGreen, or Emerald.
You need to migrate it from FireRed, LeafGreen, or Emerald. But if you have a Deoxys in Pokemon Ruby or Sapphire, then you can migrate from them to Pal Park.
You don't get a Shiny Deoxys from a man. You'll need to get Deoxys in Pokemon FireRed, LeafGreen, or Emerald. It is extremely hard to get a Shiny Deoxys.
you need to migrate from emerald or firered/leafgreen where you can get him from birth island
No you cannot. Only in Ruby,Sapphire,Firered,leafgreen,Emerald,
simply put: no deoxys is only obtainable in the Firered or Leafgreen but only with a certain ferry pass
There are sadly no special events to catch Deoxys in Sapphire. You HAVE to trade a Deoxys caught in an event from FireRed, LeafGreen, or Emerald.
You would need to use an Action Replay or transfer it from Pokemon Emerald, FireRed, or LeafGreen, for it is impossible to catch Deoxys in any location in Pokemon Diamond, Pearl, and Platinum.
You can't really get Deoxys in Pokemon Ruby and Sapphire the only way to get it into your game is to transfer it from Firered and Leafgreen and Deoxys is located in Birth Island in Firered and Leafgreen.
Get a Deoxys in Pokemon Emerald, Ruby, Sapphire, Firered, or Leafgreen using the Mystery Gift, and migrate it to your Diamond Version.
You can't get mew in firered or leafgreen.