By viewing all Pokemon in Sinohh at some point.
Capture all the Pokemon On the National Dex.
you have to fill out the pokedex first then talk to prof. Rowan in his lab
If you want to fill your Sinnoh Dex, look on websites. There are lists of where to see every Sinnoh Pokemon. If you want to fill your National Dex, you have to import them from your GBA games.
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.
You have to get national dex.
I really don't know but what I do know is that there are... I believe... 493 Pokemon to fill up the National Dex. ~Crazy Banana~
complete the pokedex then go to professor rowan and he will give you the national dex
489 i think with the national dex 150 for sinnoh dex
dragonite is in the national dex dialga is in the original dex
goldeen (or rapidash on the national dex)