yes,they are in all three gba games.
Regice: Island Cave (route 105) Regirock: Desert Ruins Registeel: Ancient Tomb (route 120)
Regirock, Regiice, Registeel, Rayquaza, Kyogre, Groudon, Latios or Latias
You can get Kyogre,Regirock,Registeel,and Regiice.
The only way is through migrating them from Pokémon Ruby, Sapphire or Emerald or by trading.
You have to have regiice, registeel and regirock to be able to fight him
Regirock, registeel, regiice, rayquaza, groudon, and kyogre
you must have regirock, registeel, regiice
You can only get a regice, regirock, and a registeel by migrating them from ruby or Sapphire. If you migrtate these Pokemon you can also catch regigigas.
you cant. regice regirock and registeel are all part of the hoen pokedex
You can get Regiice in Mt.Coronet. I think Regirock Is In the desert between the resort area and survival area. And Registeel Is at Iron Island. Oh and also you can get it from Pokemon Emerald Version. Hope This Helps
Firebug.
In Pokemon Ruby,You get Groudon,Rayquaza,Regiice,Regirock,Registeel and Latios.In Pokemon Sapphire You get Kyogre,Rayquaza,Regirock,Regiice,Registeel and Latias.If you get the Mystery event or Mystery gift,You can get the tickets to get Jirachi and Deoxys.Extra: In Emerald you can get ALL of those Pokemon (legendary Pokemon in Ruby and Sapphire).But if you get the Eon ticket from Mystery event or Mystery gift,You can go get Latios if you caught Latias and Latias if you caught Latios.(Only in emerald).