Generation IKantoGame BoyRed / Green / Blue / Yellow
Pokémon Red, Green, Blue & Yellow Gym Leaders
Version-aware Kanto Gym Leader guide with Red/Green/Blue teams, Yellow teams, recommended levels, key threats, and practical counters.
Kanto Gym progression
The Gym badge flow is largely shared across the Gen I versions, with Yellow changing some trainer and team details.
Version-aware Gym teams
Red, Green, and Blue can usually share one team group, but Yellow changes several Gym Leader lineups and should be planned separately.
Gym #1RedGreenBlueYellow
Brock - Pewter City
Boulder Badge · recommended Lv. 10-14
Version-specific team
Red / Green / Blue
Yellow
Geodude - Lower level than Red/Blue, but still resists Pikachu.
Key threats
Best counters
Practical battle notes
- Grass and Water starters are the cleanest Red/Blue answers.
- Charmander teams should train support options and avoid leaning on Normal attacks.
- In Yellow, Pikachu cannot solve this battle alone because Electric attacks do not affect Ground-type Pokémon.
Yellow-specific notes
- Yellow keeps Brock as the first major wall, but the fight is tuned around Pikachu needing team support.
- Look for early non-Electric support rather than trying to brute-force the matchup with Pikachu.
Related Pokémon
Gym #2RedGreenBlueYellow
Misty - Cerulean City
Cascade Badge · recommended Lv. 18-22
Version-specific team
Red / Green / Blue
Key threats
Practical battle notes
- Starmie is fast and punishes underleveled teams.
- Electric or Grass coverage gives the most direct answer.
- Charmander-led Red/Blue teams usually need dedicated support here.
Yellow-specific notes
- Misty's Yellow team is effectively the same as Red/Blue, but Pikachu gives Yellow players a natural answer.
Related Pokémon
Gym #3RedGreenBlueYellow
Lt. Surge - Vermilion City
Thunder Badge · recommended Lv. 24-29
Version-specific team
Red / Green / Blue
Yellow
Key threats
Practical battle notes
- Ground-type Pokémon are the safest answers because Electric attacks fail against them in Generation I.
- Diglett's Cave is the practical team-building answer immediately before this Gym.
- Yellow compresses the team into one stronger Raichu, so do not judge the battle only by team size.
Yellow-specific notes
- Yellow Lt. Surge uses only Raichu, but it is higher level than Red/Blue's ace.
- This anime-inspired setup makes the Gym feel different even though the type focus is unchanged.
Related Pokémon
Gym #4RedGreenBlueYellow
Erika - Celadon City
Rainbow Badge · recommended Lv. 29-34
Version-specific team
Key threats
Practical battle notes
- Flying, Fire, and Psychic pressure are strong into Erika's Grass-type core.
- Bring status healing because sleep and poison can slow the fight down.
- Yellow changes the exact lineup, so plan around Weepinbell and Gloom rather than assuming the Red/Blue team.
Yellow-specific notes
- Yellow Erika shifts away from the Red/Blue Victreebel and Vileplume ace pairing.
Related Pokémon
Gym #5RedGreenBlueYellow
Koga - Fuchsia City
Soul Badge · recommended Lv. 38-50
Version-specific team
Key threats
Practical battle notes
- Psychic attacks are excellent against Poison-type Pokémon in Generation I.
- Red/Blue Koga is built around Koffing, Muk, and Weezing.
- Yellow Koga is a completely different Venonat and Venomoth team with much higher levels.
Yellow-specific notes
- This is one of the most important Yellow Gym differences: Koga does not use the Red/Blue Koffing and Muk team.
- Yellow players should prepare for Venomoth's higher level and Bug/Poison profile.
Related Pokémon
Gym #6RedGreenBlueYellow
Sabrina - Saffron City
Marsh Badge · recommended Lv. 43-52
Version-specific team
Key threats
Practical battle notes
- Psychic is extremely strong in Generation I, so bulky physical attackers are valuable.
- Avoid slow Poison-type Pokémon because they are punished hard.
- Yellow Sabrina uses a cleaner Abra line team at very high levels.
Yellow-specific notes
- Yellow's Sabrina is simpler in species variety but more concentrated around the Abra evolutionary line.
Related Pokémon
Gym #7RedGreenBlueYellow
Blaine - Cinnabar Island
Volcano Badge · recommended Lv. 47-54
Version-specific team
Key threats
Practical battle notes
- Water, Rock, and Ground coverage handles most of Blaine's Fire-type pressure.
- Red/Blue includes Growlithe and Ponyta before the stronger Fire-types.
- Yellow removes the smaller team members and raises the pressure with Ninetales, Rapidash, and Arcanine.
Yellow-specific notes
- Yellow Blaine is notably higher level and more compact than Red/Blue Blaine.
Related Pokémon
Gym #8RedGreenBlueYellow
Giovanni - Viridian City
Earth Badge · recommended Lv. 50-55
Version-specific team
Key threats
Practical battle notes
- Water and Grass attacks are excellent into most of Giovanni's team.
- Keep fragile Electric-type Pokémon away from Ground-type attacks.
- Yellow Giovanni is higher level and adds Persian, making it distinct from Red/Blue.
Yellow-specific notes
- Yellow's final Gym is meaningfully tougher on level curve, especially around Nidoking and Rhydon.
Related Pokémon
More Gen I Guide Sections
Shared Walkthrough
Follow Kanto from Pallet Town to Champion with version notes.
Version Differences
Compare release history, starters, encounters, and presentation.
Exclusive Pokémon
Check version availability and trade-planning targets.
Pokémon Green Differences
Understand Japan-only Green without confusing it with Blue.
Yellow Differences
Pikachu starter, gift starters, encounter, and trainer changes.
TM & HM Locations
Find Cut, Fly, Surf, Strength, Flash, and key battle TMs.
Legendary Pokémon
Plan Articuno, Zapdos, Moltres, Mewtwo, and event-only Mew.
Elite Four
Prepare for Lorelei, Bruno, Agatha, Lance, and Champion.
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