In Pokemon FireRed and LeafGreen, trainers can go to Cinnabar Island as soon as they unlock the ability to use HM03 Surf outside of battle. To go there, trainers can either sail south of Pallet Town in a straight line or surf south of Fuchsia City through Route 19, Route 20, and then the Seafoam Islands to reach Cinnabar Island.

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How to Get Lapras in Pokemon FireRed & LeafGreen
Lapras is fairly rare to find in Pokemon FireRed and LeafGreen, but there is one way to get it easily if you know how.
How to Reach Cinnabar Island in Pokemon FireRed and LeafGreen
There are two ways to get to Cinnabar Island in Pokemon FireRed and LeafGreen:
Pallet Town → Route 21 → Cinnabar Island
Fuchsia City → Route 19 → Route 20 (East) → Seafoam Islands → Route 20 (West) → Cinnabar Island
Both of these paths to Cinnabar Island require using HM03 Surf, which can be found in the Safari Zone. Surf only becomes usable outside of battle after trainers defeat Koga in the Fuchsia Gym and claim the Soul Badge.
Pallet Town Route
Use HM02 Fly to go to Pallet Town.
Use HM03 Surf on the waterway in the southern part of town to start surfing.
Swim south in a straight line through Route 21 until you reach Cinnabar Island, landing right behind the Pokemon Mansion.
Fuchsia City Route
Head south from the Fuchsia City Pokemon Center towards the start of Sea Route 19.
Use HM03 Surf and swim southward in a straight line until the path turns left.
Head west through Route 20 (East) past the trainers until you eventually reach Seafoam Islands’ eastern entrance.
Explore the cave and you’ll eventually be able to come out to the other side through the Seafoam Islands’ western exit.
Surf west in a straight line through Route 20 (West), and you’ll be able to make landfall on Cinnabar Island, right next to the Gym.
Everything to Do in Cinnabar Island in Pokemon FireRed and LeafGreen
Despite its small size, there is a lot to do in Cinnabar Island.
Pokemon Mansion: Explore the large building next to the Cinnabar Gym to discover useful items like TM14 Blizzard, TM22 Solar Beam, Rare Candy, Moon Stone, and the Secret Key.
Cinnabar Gym: Use the Secret Key (found in the Pokemon Mansion) to unlock the doors to the Cinnabar Gym and fight Blaine. Defeating Blaine unlocks access to the Sevii Islands.
Pokemon Lab: In the Pokemon Lab, you can trade a Raichu for an Electrode, a Venonat for a Tangela, and a Ponyta for a Seel. The Move Tutor can teach a Pokemon the move Metronome. The scientist in the last room has the ability to revive fossils to convert Helix Fossil, Dome Fossil, and Old Amber into Omanyte, Kabuto, and Aerodactyl respectively.


Released
September 7, 2004
ESRB
Everyone 10+ / Mild Fantasy Violence, Simulated Gambling
Multiplayer
Online Multiplayer



