Rowans lab after you have filled up normal pokedex, prof oak will give it to you
to you but if you use the AR like me when u get 151 Pokemon and u go and try to talk to rowan he just sais go on and enjoy your edventure or sumtin like that....
In order to get the National Dex in Pokemon Diamond and Pokemon Pearl you will need to see all 150 Pokemon in the game first. After that go Sandgem Town and talk to Prof. Rowan, Prof. Oak from the Kanto region will come in the lab and update your Pokedex to national mode. If you need to see Dialga in the Pearl version go to Celestic Town and an elder woman will show you it, this gives you Dialga's PokeData to be included in your PokeDex. This is the same with Palkia for the Diamond version.
There are 151 Pokemon until you get the national dex
In Pokemon Platinum Version, there are two Pokedex'es, the Sinnoh Dex, and the National Dex. In the Sinnoh Dex, the 151 Pokemon is Manaphy. In the National Dex, the 151 Pokemon is Mew.
150 on sinnoh dex 151 if you count manaphy
Capture all the Pokemon On the National Dex.
pichu in Sinnoh Dex exeggutor in National Dex
Regional dex-unown. National dex-tangela.
the Pokemon for national dex number 124 is jynx and for sinnoh dex number 124 the Pokemon is azurill.
Unova Pokedex: Landorus National Dex: Mew
#151 is Manaphy. from turtwig to manphy, then national Dex is bulbasaur to arceus
No. Manaphy is No.151 in Pokemon platinum. Cresselia is only in the National dex at No.488 in the National Dex. If you want to find Manaphy, look at the book on the table in the Pokemon Mansion. PS~I hope this helped. I've finished the National Dex on Platinum and no cheat devices included.
complete the pokedex then go to professor rowan and he will give you the national dex
first you need to get the national dex to do this you need to see all Pokemon in sinnoh to compleat the national dex see all Pokemon on the poke dex