Getting the National Dex
After Cynthia is beaten, you’ll wake up back at home. When you hop out of bed, you'll be greeted by your mom, who will tell you that your buddy is headed up to Snowpoint to catch a boat. You might be tempted to follow him immediately, but you’ll want to hold off for now.
You’ll want to fly over to Celestic Town and visit Cynthia’s grandmother again. She’ll show you a picture of either Dialga or Palkia (depending on which version of the game you’re playing). They will then be added to your Pokedex.
Now, if you’ve been fighting all the trainers you come across and you’ve no doubt encountered the Legendary Trio, as you probably have a full Sinnoh Pokedex by now. Simply seeing a pokemon is enough to get a basic Pokedex entry on them, so if you still have any empty slots, it means there’s still a Sinnoh-native poke you haven’t encountered yet. You will need to completely fill out the Sinnoh Pokedex before doing any of the other events. If you’re missing any entries, check the following:
Have you been back to the lakes and encountered Azelf, Uxie, and Mesprit? (You don’t need to chase Mesprit down, just seeing it at Lake Verity is sufficient)
- Have you fought all the trainers in Victory Road? Several of them have rarer, fully-evolved Pokemon.
- Have you hatched eggs you have been given? You get Happiny at Hearthome, and Riolu at the Iron Island sidequest.
If you’re having issues with completing the Sinnoh Pokedex, try linking up with a friend (locally or via Wi-Fi) and trading Pokemon you’re missing back and forth. Simply being registered as an owner of a certain Pokemon for any period of time will give you a full Pokedex entry for it – meaning you can trade a friend for a Pokemon and immediately give it back and still get the Pokedex info.
(Note: Manaphy, who is obtained by transferring an egg from Pokemon Ranger, is not necessary for a full Sinnoh Pokedex!)
Once you’ve got the Sinnoh Pokedex complete, head back to Professor Rowan’s lab in Sandgem. He’ll take a look at your Pokedex and congratulate you on a job well done. Give yourself a pat on the back – you’ve earned it!
But there are more surprises yet to come – the first of which is an unexpected visitor, none other than Professor Oak from Kanto! He’ll give you two new items: The National Dex and the Pokeradar. With the National Dex, you’ll be able to track and find migrant Pokemon from Kanto, Johto, and Hoenn, and the Pokeradar can be used to help locate several of them. (See the Pokeradar section for more details.)
Talk to the professor’s assistant again, and they will urge you to head southeast. If you haven’t explored this area yet, it’s a sea route that takes you through Route 219, across Route 220 and finally back to land on Route 221. At the end of this route, you’ll find a building leading to Pal Park. Head on inside and meet Prof. Oak again. He’ll talk with you a bit and give you a new Poketch application, then head over to Eterna City.
Now that you’ve got this all done with, you’ll be able to start catching non-Sinnoh pokemon. As long as you’re in Pal Park, why not give it a shot? Get out your GBA carts and get ready to reunite with some old friends.