Celadon City is one of the largest cities in the game Pokémon FireRed. In the city you can visit various places. Unfortunately, this city is not easy to find. You can start your journey to Celadon City after defeating the Gym Leader in Vermillion City. Along the way you'll find lots of useful items and Pokémon. In Celadon City you can get a Silph Scope which is used to access the Pokémon Tower.
Step
Part 1 of 4: Leaving Vermillion City
Step 1. Go to Route 11 after defeating the Gym Leader in Vermillion City
You will cross a large cave on your way to Celadon City. HM (Hidden Move) Flash can help you get through the cave more easily. Route 11 is east of Vermillion City.
Step 2. Enter Diglett's Cave which is at the far right of Route 11
After passing through the cave, you will enter Route 2.
Step 3. Talk to Professor Oak's Aide after catching 10 different Pokémon
Professor Oak's Aide on Route 2 will give you HM05 Flash. These items are needed to pass the Rock Tunnel. To get these HMs, you'll need to catch at least 10 different Pokémon.
Step 4. Go to Cerulean City
Return to Vermillion City and keep walking north until you reach Cerulean City.
Buy potions in large quantities in the city. You will fight 15 Trainers (trainers or characters that have Pokémon) in the Rock Tunnel. Therefore, Potions will help you when fighting with them. Also, it's a good idea to buy some Escape Rope and Repel
Step 5. Pass the house that was robbed by Team Rocket
The house is in the east of the city. Use HM Cut to chop down trees that are blocking the way. Follow the path to reach Route 9 where the Rock Tunnel is located.
Step 6. Skip Route 9 and Route 10
You will fight various Trainers along the way. Avoid using Pokémon healing items when crossing Route 9 and Route 10. It's best if you only use these items in the Rock Tunnel. After entering Route 10, you'll find a Pokémon Center south of Route 10.
Step 7. Heal Pokémon at the Pokémon Center
Crossing the Rock Tunnel will take a long time and you will be up against strong enemies. Therefore, make sure the Pokémon is healed at the Pokémon Center before going there.
Part 2 of 4: Crossing the Rock Tunnel
Step 1. Use Flash when entering Rock Tunnel
HM Flash will illuminate the tunnel so you can see clearly when crossing the tunnel.
Step 2. Find the stairs to the east of the area
You have to walk down a bit to avoid the dead end. After that, walk upstairs to find a ladder that will take you to area B1F.
Step 3. Walk to the left and then up
After that, walk to the right to find another ladder that will take you back to area 1F.
Step 4. Walk down and then right to find the next ladder
The stairs will take you from area 1F to area B1F.
Step 5. Keep walking left until you reach the end of the path
After that, walk upstairs to find the last ladder.
Step 6. Find the cave exit on the south side of the wall
This exit will take you to the south of Route 10.
Part 3 of 4: Go to Celadon City
Step 1. Enter Lavender Town which is south of Route 10
Most of Lavender Town's area is dominated by Pokémon Tower. However, you can't go to the top floors of a Pokémon Tower if you don't have a Silph Scope. You can find these items in Celadon City.
Step 2. Exit Lavender Town and head to Route 8
Walk west until you see the Saffront City gate. However, you cannot pass through the gate. Therefore, you have to find another way.
To catch a Growlithe, you must enter an area surrounded by a fence and blocked by a tree. Use HM Cut to chop down a tree and enter the area. Growlithe is useful against Gym Leaders in Celadon City
Step 3. Enter the building to the north of the Saffron City gate
You can access the Underground Path through the building. The tunnel will take you to Route 7 which is to the right of Celadon City.
Step 4. Level up the Pokémon on Route 7
Before fighting Celadon City's Gym Leader, it's a good idea to level up your Pokémon first. Luckily the Route 7 grass is a good place to train your Pokémon.
Step 5. Enter Celadon City
Walk to the top left corner of Route 7 to enter Celadon City. It is one of the largest cities in Kanto. Thus, you can do various activities there.
Part 4 of 4: Exploring Celadon City
Step 1. Visit Celadon Department Store
Celadon Department Store is one of the best places to buy stuff in the game. You can buy various TM (Technical Machine) and Evolutionary Stones. Apart from that, you can also buy healing items. The place provides Great Balls that are used to catch elusive Pokémon.
Step 2. Visit Celadon Mansion to open access to Saffron City
Talk to the Old Lady on the first floor of the Celadon Mansion to get some tea. After that, talk to the guard outside the gates of Saffron City to gain access to the city.
Step 3. Get Eevee
If you have five or less Pokémon, you can get Eevee from the Know-It-All Man behind the Celadon Mansion. Use the Water Stone, Thunder Stone, or Fire Stone to turn Eevee into a Vaporeon, Jolteon, or Flareon.
Step 4. Defeat Erika at the Celadon City Gym
Erika is one of the Gym Leaders who is easy to beat because she only uses Grass-type Pokémon which has a lot of weaknesses. Fire, Ice, Bug, and Flying type Pokémon can easily defeat Erika's Pokémon.
Step 5. Fight Team Rocket hiding in the Rocket Game Corner to get a Silph Scope
Enter the Rocket Game Corner and check the poster pasted on the back. You will find the switch on the poster. Turn on the switch to open the Team Rocket hideout. You'll need to go through several floors and defeat Team Rocket members before fighting Giovanni. Giovanni's group is vulnerable to attacks by Grass, Water, and Fighting type Pokémon. After defeating Giovanni, you'll get a Silph Scope.
Step 6. Bring the Silph Scope to Lavender Town
You can use the Silph Scope to see the ghosts living in the Pokémon Tower and access the upper floors.