If I am right, it should be by entering hall of fame
only when you get the national dex on Sapphire version
tyranitar
in ruby and Sapphire,they require more work than emerald version. so u must see all the Pokemon in the Sapphire and ruby gamesAnswerNo............No..............No.No.No.No!!!! To get the national dex, you need to trade Pokemon with fire red or leaf green and you will obtain the national dex automatically. You can't get the national dex if you don't have a link cable!!!! to trade Pokemon in sapphire to fire red. In one island give Celio the ruby and sapphire and voila!!!
all you have to do is beat the Pokemon league 1 time its simple.
I think you need to see them all.
national Dex have sapphire in and iron island
its in the national park in the very southwest corner of it behind the fence.
You have to use the Pal Park option which is only available after obtaining the National Pokedex. Even then it isn't trading, you are transferring Pokemon from Sapphire to SoulSilver.
202 (Treecko - Deoxys)
from the fight area to the survival area and you may also migrate from ruby sapphire emerald migrate is to put Pokemon ruby sapphire emerald instead of the cover but you must put 6 Pokemon in the PC in ruby sapphire emerald then select in Pokemon platinum migrate from ruby or sapphire or emelard
You need to get 100 pokemon then go and talk to professor Birch and he will upgrade your pokedex.
It's possible.