How to obtain Regigigas

Obtaining Regigigas

To obtain Regigigas, raise Regirock, Regice, Registeel, Regidrago and Regieleki to level 100 and put them in your party in that order.

Then head to the underwater cave on Route 133, the same one used to unlock the Hoenn Regis. Continue to the deepest area to find Regigigas at level 100.