I don't think you can.
no, in Pearl as well as Diamond and Platinum, you can only be in the Sinnoh region
johto and kanto
You can't get there because you can only go to johto and kanto.
basically its every Pokemon from the kanto region to the johto to hoen region
Mainly Johto, but after you beat the Pokemon League you can go to the Kanto.
== ==
Get all gym badges of Johto and defeat the Pokemon league. Then you have access to the Kanto Region.
All the Pokemon that didn't exist in that particular region. Example in firered and leafgreen you can get johto and hoenn Pokemon like lugia or rayquaza. In diamond and pearl you can get stuff from kanto and johto and hoenn.
you trade with others who has the kanto, johto, or other hoen regions
you start out in the johto region if you mean kanto you have to beat all the gym leaders and the elite 4
493 Pokemon total Kanto:151 Pokemon Johto: 100 Pokemon Hoen: 135 Pokemon Sinnoh:107 Pokemon
Pokemon Pear [and Diamond] is located in the Sinnoh region. You will not be able to get to the Johto region unfortunately. Sorry.