Walkthrough
With the Cinnabar Island Gym defeated, you will now need to head to the final Pokemon Gym. Surprisingly, it is back in Viridian City. The quickest way to get there is by heading straight north on Route 21, at least if you don't want fly there and miss out on battling more Wild Pokemon and Trainers.
Wild Pokemon
Grasses:
Pidgeotto (20%): Levels 37-42
Raticate (20%): Levels 37-42
Tangela (15%): Levels 37-42
Weepinbell (14%): Levels 37-42
Pidgey (10%): Levels 37-42
Rattata (10%): Levels 37-42
Bellsprout (10%): Levels 37-42
Victreebel (1%): Levels 37-42
Grasses - Special Spawns:
Chansey: Levels 37-44
Waters:
Tentacool (30%): Levels 37-42
Staryu (30%): Levels 37-42
Magikarp (30%): Levels 37-42
Tentacruel (9%): Levels 37-42
Starmie (1%): Levels 37-42
Sky:
Pidgey (60%): Levels 3-56
Pidgeotto (35%): Levels 3-56
Pidgeot (5%): Levels 3-56
Sky - Special Spawns:
Dragonite: Levels 3-56
Charizard: Levels 3-56
Articuno: Levels 3-56
Zapdos: Levels 3-56
Moltres: Levels 3-56
Trainers
Swimmer Jerome: Level 42 Slowbro
Swimmer Roland: Level 42 Starmie, Level 42 Kingler
Sailor Claude: Level 42 Primeape, Level 42 Machoke
Fisherman Nolan: Level 42 Tentacruel, Level 42 Starmie
Swimmer Spencer: Level 42 Seel, Level 42 Seadra
Roughneck Martin: Level 42 Raticate, Level 42 Onix
Coach Trainer Pam: Level 44 Machoke, Level 44 Jynx, Level 45 Kangaskhan
Fisherman Ronald: Level 42 Seadra, Level 42 Gyarados
Fisherman Wade: Level 42 Magikarp (x6)
Obtainable Items
PP Up: Small Island Near Cinnabar Island
Poke Balls: Defeat Swimmer Jerome
Poke Balls: Defeat Swimmer Roland
Poke Balls: Defeat Sailor Claude
Poke Balls: Defeat Fisherman Nolan
Water Stone: Near Fisherman Nolan
Poke Balls: Defeat Swimmer Spencer
Poke Balls: Defeat Roughneck Martin
TM35: Defeat Coach Trainer Pam
Poke Balls: Defeat Fisherman Ronald
Poke Balls: Defeat Fisherman Wade
Hyper Potion: Near Fisherman Wade
Stardust: Southwest Island
Post Game
Walkthrough
After defeating the Elite Four and starting the Master Trainers Challenge, you will find a number of Master Trainers on Route 21. In total, there will be three Master Trainers to defeat.
Trainers
Swimmer Nicole (Master Trainer): Level 70 Psyduck
Swimmer Jill (Master Trainer): Level 70 Slowpoke
Swimmer Haruka (Master Trainer): Level 75 Slowbro