you need to have the sinnoh dex completed and i think beaten the elite four and the champion. then you need to get the 3 regis from a sapphire, ruby or emerald game and then get them onto a diamond,pearl or platinum, put them in your Pokemon party and go into the temple in snowpoint city. regigigas will be at level 1.
You have to have a special Regigigas from an event.
No; you cannot catch the three Regis in Platinum, UNLESS you have obtained a special Regigigas through some special events.
in the snowpoint temple
You don't. You can only catch Regigigas in Diamond, Pearl, and Platinum.
Trade with Pokemon Platinum, Pearl, or Diamond.
First, get Pokemon Platinum. Get the special Lvl 100 Regigigas in your party* and go to Mt. Coronet. Then trade it to Heart Gold/Soul Silver. *The special Lvl 100 Regigigas is only available through Pokemon Events.
only with a hacking device.
Fight the elite 4 and just train your Pokemon
I'm sorry but you only have one chance to catch him
You need a event Toys R Us Regigigas.
You can't because regigigas is a 4th gen pokemon. If you want a regigigas then you will have to migrate Regice, registeel and regirock to Diamond, Platinum or pearl
You need relicanth and wailord to catch the regis in sapphire/ruby/emerald. You cannot catch the three regis in platinum unless you have the event Regigigas (this event has now ended). If you have the special regigigas in your party, three new caves will open up in Sinnoh and you will be able to catch the three regis.