You can go through this route to reach Fuchsia City, where the next Gym is located. To get here, simply travel south from Lavender Town. After Route 12, you’ll have to go through Route 13, Route 14 and Route 15. It’s a long, long road, so remember to pack all your essentials!
Anyway, we’re going to assume you’ve already explored half of this route earlier. If not, please refer to the Route 12 (Part 1) page in the Gym 4: Rainbow Badge chapter. Once you reach the halfway point of Route 12, use the Poké Flute to wake up Snorlax.
The Poké Flute
To obtain this key item, you’ll need to trigger these events in the following order: Encounter the ghosts on the 3rd floor of Pokémon Tower, bump into Team Rocket by the west exit of Lavender Town, obtain the Silph Scope in the Team Rocket Hideout, then reach the top floor of Pokémon Tower.
Mr. Fuji will suddenly come rushing in from Lavender Town to warn you. Oops, it’s a bit late for that, as the wild Snorlax will immediately attack you.
Wild Pokémon: Snorlax
Wild Pokémon Battle
This is one of the few times you can actually battle a wild Pokémon. Unlike normal battles, you’ve got a 5 minute timer that will keep counting down. If time runs out, you’ll lose your chance to catch Snorlax for now. As such, we recommend saving before proceeding. In addition, your aim is to KO the Pokémon.
Snorlax has impressive Special Defence, so you want to focus on using physical attacks, especially super-effective Fighting-type ones. For attacks, it can use Headbutt to cause damage, Lick to annoy non-Normal Pokémon, Yawn to induce Sleep, and Rest to fall asleep and recover all HP.
When the battle starts, Snorlax will get boosted Attack. But surviving Snorlax usually isn’t the main problem–it’s defeating it that can be tricky, thanks to its bulkiness and Rest. If you don’t have Fighting-types, you can consider summoning a Support Trainer (Player 2) to assist you. Don’t worry, nobody’s going to judge you!
After defeating Snorlax, you will immediately enter catching mode. Because it’s so big, Snorlax doesn’t move around much, if at all, but it does jump up and down every now and then. This is where you want to use Ultra Balls–and maybe borrow a Support Trainer’s help.
Once Snorlax is no longer blocking the road, you can continue south and begin your long journey to Fuchsia City. For reference, heading west will take you back to Route 11, near Vermillion City. After the next corner, there’s a Fisherman on the right who likes to look up and right.
Tentacool is also a Poison-type, so it’s weak to Electric, Psychic and Ground. Stick with the former two, since Ground-types are weak to Water. Kingler is an evolved Krabby and carries a mean Crabhammer. Grass-types are ideal, but from an offensive standpoint, Electric-types are just as effective.
Below, there’s a house in the middle of an island. Go inside and chat to the elderly man on the right. He used to be the Move Deleter, but now he’s got a new identity, as the giver of TM32 Dazzling Gleam. This is a rare Fairy-type that hits both opponents during a Double Battle. But it’s quite strong even during normal battles.
Exit Mr. Dazzling’s house and continue south along the left-hand side pier. If you’re curious, go over to the costumed trainer standing on the edge of the pier. Oh, he’s not here to battle. Further south, there’s a skinny tree along the left that you can remove using Chop Down. Past the tree, you’ll have to fight a trainer to grab the item.
Luca’s Electabuzz has a pretty strong Thunderbolt. So that’s even more reason to field a reliable Ground-type.
Go past Luca and pick up the item to find it’s a Water Stone. Well, you could’ve bought one from the Celadon City Department Store, but never say "no" to free stuff! Nearby, to the right is a Camper who also likes to turn around–left and down. Past him is an Awakening lying on the pier.
Gosh, a Nidoran (male). Seriously? Why hasn’t he evolved the poor thing? But don’t lower your guard, as it packs Toxic, for severely poisoning opponents, and Horn Drill for a surprise one-hit KO.
Nidorino is a bit more acceptable at this stage. This evolved Nidoran (male) also has Toxic. So take it out fast with super-effective Ground or Psychic-types unless you like to waste Antidotes and Full Heals. Otherwise it’s a joke.
A little ways south, there’s a Coach Trainer towards the left.
Coach Trainer Priya
Butterfree is a fully evolved Caterpie. It’s also Flying, so it takes massive damage from Rock, and the standard super-effective damage from Fire, Electric, Ice and Flying. It can use a STAB-boosted Bug Buzz, Sleep Powder to cause sleep, and Dream Eater to steal HP from sleeping foes.
Clefable is an evolved Clefairy. It’s still a Fairy-type, so weak to Poison and Steel. It has a similar kind of moveset: a STAB-boosted Dazzling Gleam, Sing to induce sleep, and Dream Eater to sap health from Pokémon that fell foul to its lullaby.
Wake up Priya and she’ll give you TM59 Dream Eater. If you didn’t experience it during the battle, this is a powerful Psychic-type move that deals impressive damage and restores the user’s HP. But only if the foe is asleep. Pokémon that use Rest to fall sleep are also applicable.
After Priya, the pier will flow south in a mirrored "C" shape. To the left is another skinny tree that you can Chop Down. Past here is a patch of tall grass. Go towards the middle and you should spot a Max Lure in the tall grass. Return to the pier and carry on following it south. You’ll reach the next route before long.
The main new addition here is Farfetch’d, a rather peculiar Flying-type Pokémon. There’s also Gloom (Let’s Go Pikachu), Weepinbell (Let’s Go Eevee) and Kingler if you’re lazy–or just busy–to evolve your Pokémon.