it is very hard to catch all Pokemon you have to use your pokeradar, migrate Pokemon, insert gameboy games and catch unusual Pokemon, talk to Dawn's/Loran's sister, trade, and events
You can catch Sinnoh Pokemon in Pokemon platinum, but you need to migrate and trade unless you have an action replay
You catch them.
how do you catch a mewtwo on Pokemon platinum
you cannot catch the 3 regi's in Pokemon platinum you have to catch them in Pokemon emerald then transfer them to Pokemon platinum. thnx
To finish the sinnoh dex (Pokemon platinum's,diamond, and pearl dex) you just need to see every Pokemon not catch every Pokemon.
You can catch and find all the sinnoh Pokemon and when you see all the sinnoh Pokemon you get the national dex and find and catch all the pokeradar Pokemon.You get the pokeradar when you get the national dex.
You catch Garatina, Dialga,Palkiia,and all the lake Pokemon but mainly Garatina
You can't get Thunderus in Pokemon Platinum at all. By then when Pokemon Platinum was made, no one knew that Pokemon Black and White were going to be made.
depending on where you go and what you do you can catch all of them, every Pokemon in existence
No. You can only get 1
You can't actually catch him in Pokemon platinum but you can migrate him over to platinum if you have him in another game
you can't catch him in platinum but in soulsilver or heartgold you can catch him then trade it to platinum.