You have to challange every trainer in the game (including Elite 4 and the Champion, since Cynthia is the only one who has a Spritomb and Milotic) and after you battled against Dialga you have to go to Celestic Town to talk Cynthia's grandmother so that she will show you the picture of Palkia; or you can trade and get the Pokemons that you didn't see.
in order to catch every Pokemon in diamond you would have to fill up your pokedex and trade on GTS. or trade your Pokemon from diamond to pearl. or the other way around. there are Pokemon in diamond that you can only get from pearl.same thing the other way around.
First, go in the grass a lot. You will need to fight and defeat or catch the Pokemon to add their data to the pokedex. Evolving will also help you since you can't see certain Pokemon unless you evolve them. Second, battle with every trainer you can. Also, trade with your friends. Lastly, battle the Elite four. To see Dialga in Pearl, go to the large building in the center bakc of Celestic town after you defeat Palkia. Talk to the Old woman on the left. She will show you a picture of Dialga and the data will be added to your pokedex. Do the same thing in Diamond for Palkia.
you just have to keep traveling. every town there is a new Pokemon to see. other than traveling, battling trainers and trading with friends is a great way to meet and see new Pokemon. you might not see EVERY Pokemon, but you'll see most of them.
In order to see all 210 Pokémon in Pokémon Platinum for the Sinnoh Dex, you have to battle every trainer that you see however there are 3 Pokémon that trainers do not have and they are Unown, Rotom and Manaphy. Unown can be found in the Solaceon Ruins but they only activate there once you've gotten the HM Defog, Manaphy can be added as "seen" to your Sinnoh Dex if you examine the book in Mr. Backlot's room in the Pokémon Mansion and Rotom can be seen and caught if you head into the Old Chateau in Eterna Forest, go upstairs, head left and go into the first door that you see then click on the TV and if it's between 8 PM and 4 AM in your game then a Rotom will come out however this is your only chance to catch a Rotom as well.
You have to go across whatever region you are in (or all regions if that's what you mean), visiting every place many times until you see all 500 pokemons in that game.
Simple. Work hard,use your pokedex,buy a lot of pokeballs and trade with as many
trainers you can.
you have to see all the Pokemon in sinnoh
you have to be playing with a friend to see him or her down there
Yes, but its for platinum only, if u have all the lake pokemons (Mespirt, Uxie, and Azelf) bring 'em to the cave... Click on the etching of the lake pokemon, and a special pokemon will appear, exlusive for Platinum Only
at www.serebii.net
In the Safari Zone.
You have see to many different pokemons. Then you will fill it (you have to every Pokemon to get national pokedex).
Will? oh ketchup, that game came out a long time ago. check out the sinnoh pokedex. google it.
First u need 2 see all the pokemons in Platinum (u can see some of them when u battle the pofemon league in platinum). then go to prof.rowans lab in sandgem town and then talk to him and he will give u the national dex. hope this helps
battle everyone
see all 210 Pokemon
you see all the Pokemon in platinum and trade from your other games like emerald, blue, fire red etc and that is how you find all Pokemon in platinum.
You have to see all 210 pokemons or find the national pokedex cheat code at http://www.cheatsguru.com/nds/pokemon_platinum/cheats/1828918.htm . Enjoy. PS I need one more Pokemon till I get the national pokedex!:)
ask a friend that has Pokemon platinum that has good pokemons and things like that to meet you in the union room and then youll see ur friend
you have to see all the Pokemon in sinnoh
go to psypokes.com :) and you can see all about Pokemon games.
You have to see all Pokemon Pokemon. But not the ones on nationaldex.
go and see all the Pokemon in the sinnoh dex