Most people to get to Cinnabar island would surf beneath Fuchsia city and try to weave they're way through the Seafoam islands. There is a shortcut however--you don't even have to go this way. If you just go to Pallet town you can go down and surf until you reach Cinnabar island.
It's very simple. Just go to Pallet Town and walk to the south, until you reach the sea. Then just surf to the south until you reach The Cinnabar Island.
You can also go through Seafoam Islands, where you can also catch Articuno, but you can do it later though. If you choose this way, you will need a Pokemon that knows Strenght (HM04) with you. You can't manage through Seafoam Islands without Strenght, you need to move some boulders there. When you reach the other entrance of Seafoam Islands, just surf to the west, until you reach The Cinnabar Island. Remember buy an escape rope ant take it with you, just in case you get lost.
You have to surf south of Pallet Town to get to Cinnabar Island.
Surf down from pallet town
Surf South from Pallet Town
you catch it at mt.ember in one island. you will be able to go to one island after defeating blaine, the gym leader of cinnabar island.
You will need to work your way to the basement in the Pokemon Mansion, you will then find the Key.
Its inside a pokeball inside the Pokemon mansion on Cinnabar Island
On cinnabar Island, to the left of the pokemon center, lies a "laboratory". If you go inside, then go to the right and enter the third door. Talk to the Professor there.
If you mean Pokemon FireRed/LeafGreen on the GBA, the mansion is in the top left corner of Cinnabar Island. (home of the seventh gym)
on cinnabar island
Cinnabar Island
there is no cinnabar island in sapphire. cinnabar is on firered and leafgreen. also in Pokemon yellow special pikachu edition ^_^ don't forget that dude...
Cinnabar Mansion on Cinnabar Island, that is, if you're playing FireRed/LeafGreen!
Cinnabar island use a great rod.
The 7th gymbadge is in Cinnabar Island
Cinnabar island
Surf from Cinnabar island left there you can get in.
Seafoam Island - East of Cinnabar Island - Southwest of Fuschia City
in the Pokemon mansion that is where than is on cinnabar island
you have to go inside the dungeon on that island and find the exit on the other side
Cinnabar Island where the burnt down Pokemon mansion is found is not available in Pokemon Emerald. This location is available in Pokemon FireRed and LeafGreen.