1.you need the azule Flute which you can get at an event.
2.go to the top of the mountain that is left of Hearthome city.
3.use the azule flute.
4.go up the mysterious stairs
5.use strong pokemon because he is level 90.
enjoy
sorry you can't get oshawotts in Pokemon platinum and there aren't any cheats to get one.
You Have to trade from Pokemon Diamond, Pearl, or Platinum.
I think so. Because I did but with cheats.
you can using cheats,trade or using pal park but without 1 of those 3 u cant
You can only get Kyogre through cheats, Pokemon Saphire, or a trade. Sorry but there's no other ways then that.
how do you catch a mewtwo on Pokemon platinum
you migrate a lv 100 Pokemon from GBA, then catch it in pal park hope this helps (buy used gba they probably have good Pokemon)
you cannot catch the 3 regi's in Pokemon platinum you have to catch them in Pokemon emerald then transfer them to Pokemon platinum. thnx
you do not catch purge in diamond pearl or platinum. Purge is a fan created pokemon.
you can't catch mew in Pokemon platinum you can only get it by cheats, mystery gift, migrate from a Game Boy Advance Pokemon game like fire red, leaf green sapphire, ruby, or emerald version.
You can catch them on Iron Island once you have the National Pokedex. You get this by seeing all the Pokemon on the Sinnoh Pokedex.
dependind on what system you are using (ds or Pc) you would have to use trading (ds)or cheats which are easier (pc)