You need to get to the end part where Kyogre and Groudon are having that battle, just after you've gone to get Rayquazua. Jet back to the Weather Institute and the guy will tell you "Major drought" in one area, which is Groundon's place, and "Heavy rain" in another, which is Kyogre's. You need to DIVE where the dark spot in the water appears (the one that normally isn't there). If I remember correctly, Kyogre is just off Mossdeep City and Groudon is in that cave west of Mauville.
---PokeFreak
it tells you how to unlock the regis
You can get a rigirock on Pokemon Emerald in the Desert Ruins.But you need to unlock the Rigi's though,before you can attempt this.
you cant
You can get a Rigisteel on Pokemon Emerald in the Ancient Tomb,which is on Route 120.But you need to unlock the Rigi's before you can attempt this.
By finding them in the wild, evolving, or trading... fairly simple
it's impossible
hoenn region.
Find the key at a under water cave
watch "how to get the three regi's" on youtube
No, the only way to get them is to migrate them from R/S or Emerald.
you beat Kyougre or catch Kyougre in the cave of origin then when its not raining go to wallace's gym!
Go to this link for all you need to know and its a great site for all Pokemon info and its not some stupid website its really good http://www.psypokes.com/emerald/legendaries.php