first you have to defeat the 3 commanders at the 3 Great Lakes then.......then when you get to Cyrus and defeat him in the distortion world you back to the place where the man was and he's gone.therefore you now have access to sunnyshore city.
You have to beat Cyrus on Mt.Corent
Go east past Route 222, south of Route 223. More information can be obtained by going to the web-page through the "Related links" section below.
you get secret potion from Cynthia after you chase galactic grunt in pastoria city
u gota break snoballs and get to the front and get speed
that's easy you have to defeat the snowpoint and team galactic before you can even go to sunnyshore.if you still can't maybe you forgot to do something like battle a galactic grunt i know i did but now i finishedhope i helped
=you have to of done all seven badges to get there. You shold be able to after then. By the way the 8th gym is in sunyshore city.=
East of Jupilife City all the way at the end. You'll see the cave and go past through there and you'll be in Oreburgh City.
u cn find mothim when u are travelling down past veilstone city go south of that and u cn find it
beat snowpoint city gym then get palkia if you have Pokemon pearl or go and get dialga if you have Pokemon dimond then try again then you should be able to get there.
cach pearl the legndary Pokemon
Past the elite four.
You go to the light house and talk to the yellow head freak he'll say some stuff an then go's to the gym go back to the red head freak and he'll move to the elite 4 were he'll be waiting to battle you now you get to battle the yellow head freak Volkner. I segest if you have Dialga teach him earthquacke and if you have Infernape you teach him dig.