Route #30 and Route #31 are relatively uncomplicated roads—unfortunately, you'll have to wander off the path to climb uphill. You'll be wandering through tall grass again, but it will help your Pokémon become strong—if you win.
New Pokémon to catch
Routes 30 and 31 contain a variety of new Pokémon (especially Crystal), so bring several Poké Balls. Bug type Pokemon are plentiful here in all versions. Caterpie appears in Gold while Weedle appears in Silver. Two new Pokémon also appear: Ledyba (morning in Silver) and Spinarak (night in Gold). Unfortunately, they are all very weak (even Butterfree and Beedrill) and will be useless in the first gym. Bellsprout, though weak at the first gym, is decent and very useful if you did not choose Chikorita as your starter. Crystal gets all of the previously mentioned Pokémon, plus three more! Gastly, Zubat and Poliwag are organized only at night and are rare but worth capturing them. Poliwag appears only on that route, Gastly and Zubat will be found in other places more easily, so do not worry if you miss those two.
At this point, if you can, train your starter enough to evolve it to its second form. Cyndaquil will evolve into a Quilava at level 14, Chikorita will evolve into Bayleef at level 16, and Totodile will evolve into Croconaw at level 18. Most enemies here are weak to Fire and Flying-type attacks, so use this to your advantage.
Trainer battles begin
When you return to Route #30 after completing your errand, trainers will attack you whenever you make eye contact. As you can see from their rosters below, their Pokémon are weak, but they can wear you down. You can try to avoid them, but it's better to fight when you can: they're the best source of money and EXP in the game.
One new twist is the ability to trade phone numbers with certain trainers once you've defeated them in battle (they will say phone next to their rewards). If you agree, they'll call you periodically to chat, challenge you to rematches, and most importantly, inform you of Pokémon "swarms." Without that info, it's hard to catch Pokémon like Dunsparce in the nearby Dark Cave.
Catch a Bellsprout (or two)
The dividing line between Route #30 and Route #31 is right about where the trainer named Don waits. To the north of him you'll find pretty much the same Pokémon you found below, but with the addition of Bellsprout and Gastly. Try to catch an extra Bellsprout—not because they're that great, but because they can be used to trade for a very useful Onix in Violet City.
Run an errand and get TM 50
A little later in the game, a guard in the guard house that separates Goldenrod City and Route #35 will send you to deliver a message to the guy in front of the lake, so remember where he is! Finishing this errand is the only way to get TM 50, Nightmare.
Trainers and items
|Route #30 Trainers||Route #31 Trainers|
|#60 Poliwag||#10 Caterpie|
|Poliwhirl you can then use a Water Stone or trade it with a King's Rock to get a powerful Poliwrath or Politoed. But don't evolve it too early: Each of those forms can learn two exclusive moves, but none of them are anywhere near as good as the Hydro Pump that Poliwag and Poliwhirl would learn if you didn't evolve them until much later.||Butterfree, at level 10. The speedy evolution is nice, and Butterfree is useful for a while after it learns Confusion at level 10. Unfortunately, its awkward mix of types and lack of other good early moves makes it a poor long-term choice.|
|#13 Weedle||#167 Spinarak|
|Beedril, actually gets a handful of strong moves: Fury Attack at level 10, and Twineedle, Pursuit, and Pin Missile later on. Beedrill is hardly the game's best Bug Pokémon, but it will hold you over until you get a Scyther.||Ariados at level 22) is Spider Web, a useful technique that prevents a Pokémon from running away.|
|#41 Zubat||#165 Ledyba|
|Crobat, who evolves from a very "tamed" Golbat, doesn't have any new moves, but it can learn Fly and is much quicker than Golbat.||Ledian are primarily defensive Pokémon, learning moves like Reflect, Safeguard, and Light Screen. They do learn a few early attacks like Comet Punch, but their Attack is too low to put them to good use.|
|#69 Bellsprout||#92 Gastly|
Weepinbell, and Victreebel are still among the least useful Grass Pokémon, and their one new move (Sweet Scent) isn't worth much. But if you didn't pick a Chikorita as a starter, you may find Bellsprout to be temporarily useful. They start with Vine Whip, which is good against the Gastly in Sprout Tower and great against Rock-type Pokémon in the upcoming Union Cave.
Bellsprout and its evolved forms can learn HMs: Cut and Flash which will soon be encountered.