you need a relicanth and a wailord
you cant get all the regis only regigigas.
When you need to find the the ruby and sapphire, when you need to find the regis...
You can't find all the regis (without the use of an event Regigigas) in Platinum but you can find Regigigas and you need Regirock, Regice and Registeel to enter the Snowpoint Temple and if you have action replay you can try catching the 3 regis too.
Actually you're wrong you can NOT get the regis in Pokemon diamond, to get the regis you need Pokemon ruby/Sapphire/emerald you can get all three regis there(regi ice, regi steel, regi rock) althought if you migrate all of the regis onto Pokemon diamond you can get regi gigas(king regi) you will find him in the snowpoint temple after beating the elite four. Thanks hope i helped ^.^
You need to get the special movie Regigigas.
to find regigigas in Pokemon platinum you need to trade over the regis from another game and go to the bottom of snowpoint temple with the regis in your team. you will see a regigigas statue and it will come to life if you have the regis in your team.
you only can find him in snowpoint temple in snowpoint city but you must have all three regis. bring all three regis go up to him and press A and the three regis will awekening him. hes a level 1 so have a goodb time catching him.
you get the regis in emerald ruby or sappaire those are the only way
u cant.. only in platinum
You need to transfer all 3 of the regis from you ruby,sapphire, or Emeralds game packs
all you really get is regigigas but you need the other three regis to awaken it
You need to have all 3 regis and go to the snowpoint temple.