There is no way you have to compleate the pokedex but most of it is at the gyms.
in the national pokedex: arceas in the regular pokedex: dialga
To get the national dex, you first have to have SEEN every Pokemon in the regular pokedex. Then talk to Prof. Rowan.Then Prof. Oak will barge in say some stuff then he upgrades your Sinnoh pokedex to the Nationaldex
On your regular pokedex once you go to switch pokedex you will have the national pokedex which all the Pokemon u can have in the game. At least that's what I say if you're saying "how is there 493 Pokemon"......
You need to see all pokemons in your regular pokedex just see them (Wifi battle doesnt count)
To get the National Pokedex, you must see all of the Pokemon that are in your regular Pokedex. You do not have to capture all of the Pokemon, but merely seeing them is enough, and it doesn't matter what gender the Pokemon is either.
you must beat the Pokemon league and complete both the regular pokedex and the national pokedex
Unfortunantely, it's impossible to catch ANY Pokemon from the National PokeDex in Ruby and Sapphire. You have to trade with FireRed, LeafGreen, Emerald, Colosseum, or XD to get Pokemon from the National PokeDex. If you trade with the first three games, you'll actually get the National PokeDex in Ruby and Sapphire.
There're 156. National Pokédex nos. 494 to 649.
210
There are none but there ARE the National Dex Complete and Shiny and Regular Pokemon Modifier. NOTE: SHINY AND NATIONAL COMPLETE CODES ARE EXTREMELY LONG!!!
You have to complete the regular pokedex and obtain the national one. then the guy will leave and there will be a pokemon trainer, marley, who will team up with you to get to the end of the cave
The Pokeradar allows you to find Pokemon outside the Sinnoh Pokedex. In a patch of grass, while using the Pokeradar, you can find Pokemon that you couldn't normally find in regular gameplay before obtaining the National Dex. To use it, you simply walk into Tall Grass, then go into your Key Items pocket. Scroll down till you find the Pokeradar, then select Use. Some patches of grass will shake around you; just go into one of the shaking patches of grass to encounter the Pokemon. There is a chance where you would find Pokemon outside the Sinnoh Pokedex, making the National Dex slightly easier to complete.