you have to have the three regis in your 6 Pokemon then go to snowpoint city go into the temple regigigas will be in there.hope this helps:)
mystery gift
1 in Pokemon Platinum Version
Get Regigegas from the giveaway and go into the cave on route 224
The regis(except regigegas),raquanza,groundon,kyogre,and latios or latias
you need a natraldex you go to the snowpoint temple go all the way to the bottem and you will find it hope this helps
You have to transfer from Ruby/Sapphire/Emerald the three Regis, then Regigigas will wake up.
migrate regirock, regice, registeel, and then you can access the regigas (migrate from emerald, ruby, or sapphire)
In Pokemon emerald [the game I know it works with] you have to catch regice,regirock,and registeel and then migrate them from your Ds.
You cannot catch it on Pokemon firered only on diamond pearl and thhe new one Pokemon platinum
You have to have the National Pokedex, have someone trade you a Regigegas, then go to Iron Island, then Mt. Cornet, then look in the desert above the Resort area.
You need to transfer all 3 of the regis from you ruby,sapphire, or Emeralds game packs
Snowpoint temple only if you have regirock registeel and regice but to get those you need regigigas in a giveaway its an endless chain unless you go to events