You have to enter the Pokemon League.
The 5th gym leader in Johto is Chuck. He is located in Cianwood City.
Where you battled the first gym leader
The gym is in blackthorn city go west then north
Bugsy in Azaelea town!
the fith gym leader in crystal is on an Island in the southwest of Johto. use surf to get to him
Whitney at Goldenrod city.
After You Defeat All The Gyms Jasmine The 8th Gym Leader Of Johto Should Give It To You.
After you have battled and beaten all eight gym leaders of Johto, you get on a ship to the Kanto region. Professor oak should be at Pallet town but you will have to beat most of the Kanto Gym leaders to get to him. Good Luck!
Falkner is the first gym leader in the Johto region. He uses a Lvl 9 pidgey and a Lvl 13 Pidgeotto, so he's not as much of a pushover as he was in G/S/C.
go to vilet city.
The Johto Gym Leader Jasmine from Olivine City is in Sunyshore City.
The 6th gym leader in Johto is Jasmine of Olivine City, and her Pokemon are as follows: Magnemite lvl 30 Magnemite lvl 30 (Yes, two magnemites) Steelix lvl 35