Have you completed Islands 1-3 (Part 1) if not meet with Bill outside Cinnbar Gym or if you've refused head to Vermillion. Islands 1-3 can be quite useful for training your team for the final gym.
Fly to Viridian City now you've completed Gym 7, the last gym will be open.
Seafoam islands is east of cinnibar island and southwest from fuchsia city.
Its located to the right of cinnibar island also if you go southwest from fuchsia city you can reach there as well.
On cinnibar island.
seafoam islands. surf from cinnibar
Head to Cinnibar Island for your next badge.
Go to Pallet Town and Surf down, and you will get to Cinnibar Island. You need to get the secret key from the pokemon mansion on Cinnibar Island to get into the gym.
You need the secret key which is found in Pokemon mansion which is also on cinnibar island.
You give it to the scientist in the cinnibar island lab that asks for fossils.
Omanyte can be gotten at the Cinnibar Island Pokemon Lab. You have to revive a Helix Fossil, which you can get in Mt. Moon, to get one.
The secret key is hidden in the basement of Pokemon Mansion which is located on Cinnibar Island.
Go to the lab in cinnibar island and give it to the scientist in the last room he will turn it into aerodactyl!
The key is hidden in the basement of Pokemon Mansion which is located on Cinnibar Island.