Go through Mt. Coronet use rock climb to the right of the river thing. then proceed throughout the mountain catch dialga/palkia/giritina then go to the man at valor lake front and go right to sunnyshore
You cant go to sunnyshore city until you have 7 of 8 badges and you beat the vielstone HQ after getting the 7th badge. good luck!
you have to get to the top of mt.coronet and fight team galactic and catch or kill dialga. then go to sunnyshore city the guy will let you thru. then walk thru the path and boom. sunnyshore and the 8th gym!
You have to go to cinnibar island and meet up with Blue. Talk to him. He will then go back to Viridian City Gym and you can face him.
go to sunnyshore city
After you get the last badge in Sunnyshore City, go the north-most point on the beach and you will meet a girl named Jasmine, a Johto gym leader. She will be impressed by your efforts and will give you HM07 - Waterfall. REMEMBER, YOU NEED TO HAVE BEATEN THE GYM LEADER IN SUNNYSHORE CITY AND RECIEVED THE BADGE. SHE WILL NOT GIVE YOU THE HM IF YOU HAVEN'T.
The 8th badge is the Beacon Badge in Sunnyshore City. First, you have to have caught Dialga. Then when you go to Sunnyshore City, one of the Elite people will come up to you and tell you to battle the gym leader. Except he's not at the gym. He's in the lighthouse in the lower right hand corner of the town.
You need to go to the distortion world. And finish this story line. Then you will be able to go to Sunnyshore city. Then you'll have to go to the Lighthouse to find the gym leader. Then you can fight him at his gym
You need to battle Girtina in the Reverse \World then you will be able to go to Sunnyshore
You must go to Sunnyshore. It is by Vielstone and Pastoria. Just take the path to the east.
You go to get your 7th Badge in Mossdeep City.
you go to mt.coronet,go all the way to spear pillar and you find palkia then you go to sunnyshore city and get the 8th gym badge
go to snowpoint city and beat the ice gym then you will get your badge.