you have to find and talk to the gym leader (Volkner) before you can fight him. he's at the top of the lighthouse tower
You have to go to the Lighthouse in Sunyshore City and he will be there. Talk to him and he will go back to the gym. When you get to the gym, Flint will still be standing there. Talk to him and he will move.
To get to sunyshore, you have to get the snowpoint city gym badge.
You can get to Sunyshore city in Pokemon Pear after you defeat the first seven gym badges and Cyrus at the stone pillars. The entrance to Sunyshore is to the right of the beach resort.
Its at lake volor. basiclly the lake near the water gym place is and the entrance to the route to sunyshore city
After going by the Gym, you will see that Flint is there and he will not let you in. You will need to head to the Lighthouse and you will find Volkner, the Gym Leader of Sunyshore City there. Talk to Volkner and he will leave the Lighthouse and he will return to the Gym. Now you can head back to the Gym and you will be able to enter it.
Start at the entrance to the town: Go up the stairs by the entrance. Keep on going right. Go on the first path to the north. Now go left. Good luck beating the gym leader!!!
get the 7th gym badge
Once you talk to Flint in front of the gym itself, travel on the panels and go inside the lighthouse. He should be in there. He'll ramble on for about a minute, and then you can go to the gym and you may go inside.
sunyshore city dudes
victory road north of sunyshore city but you have to have the sunyshore gym badge to get there
HM07, Waterfall, is given by Jasmine (Olivine City's Gym Leader) after defeating Volker, the Sunyshore City Gym Leader. You can find Jasmine on the beach in the northwestern-most corner of Sunyshore City, just south of sea Route 223.
The last Gym is in Sunyshore City.