Part 1: Before your first gym badge

The opening stretch around Littleroot, Oldale and Petalburg, before you've beaten a gym leader.

Before your first gym badge opens 10 areas. There are 40 trainers standing in them. The fights at this checkpoint are Gym Leader Greta, Lass Tiana, Lady Cindy, and 7 more.

Where to go

1. Oldale Town

   Wild: Barboach 70%, Pelipper 60%, Whiscash 60%, Lumineon 40% +7 more

   Trainers: Triathlete Marcus Lv 3

   Pick up: Old Rod

   Move tutor: Nuzzle, Shadow Sneak, Sand Tomb, Twister, Disarming Voice, Absorb, Bubble, Clear Smog, Snatch, Teleport

2. Route 103

   Wild: Corphish 70%, Crawdaunt 60%, Pelipper 60%, Barbaracle 40% +7 more

   Trainers: ★ Fisherman Andrew, ★ Rival Brendan/May (Grass) Lv 5, ★ Rival Brendan/May (Water) Lv 5, ★ Rival Brendan/May (Fire) Lv 5

   Pick up: Focus Sash

3. Route 102

   Wild: Poliwag 70%, Gyarados 60%, Whiscash 60%, Poliwhirl 40% +8 more

   Trainers: ★ Lass Tiana Lv 6, ★ Lass Tiana Lv 5, Youngster Calvin Lv 5, Bug Catcher Rick Lv 4, Youngster Allen Lv 4, Youngster Allen Lv 4

   Pick up: Poison Barb, Oran Berry

4. Route 104

   Wild: Poliwag 70%, Lanturn 60%, Politoed 60%, Crawdaunt 40% +6 more

   Trainers: ★ Lady Cindy, ★ Lady Cindy

   Pick up: TM09 Bullet Seed

5. Petalburg Woods

   Wild: Blipbug 20%, Paras 20%, Phantump 20%, Skiddo 20% +1 more

   Trainers: ★ Bug Catcher James, Bug Catcher Lyle, Team Aqua Grunt

   Pick up: TM57 Charge Beam, TM77 Struggle Bug, Miracle Seed

6. Route 115

   Wild: Clauncher 70%, Clawitzer 60%, Mantine 60%, Barbaracle 40% +4 more

   Trainers: ★ Rival Midori, ★ Rival Midori

   Pick up: TM42 Facade, TM69 Rock Polish, TM97 Dark Pulse

7. Route 116

   Wild: Drifloon 20%, Impidimp 20%, Shinx 20%, Swirlix 20% +3 more

   Trainers: ★ Youngster Johnson & Hiker Devan, Youngster Joey, Youngster Joey, Bug Catcher Jose, School Kid Karen, Hiker Clark +4 more

   Pick up: TM98 False Swipe, Black Glasses

8. Rustboro Gym

   Trainers: ★ Gym Leader Greta Lv 16, ★ Gym Leader Greta Lv 16, Youngster Tommy, Gentleman Marc, Youngster Josh

9. Route 104 South

   Trainers: Youngster Billy Lv 8, Youngster Billy Lv 7, Fisherman Darian

10. Route 104 North

    Trainers: Rich Boy Winston, Lass Haley, Twins Gina & Mia, Fisherman Ivan

★ Gym Leader Greta — Rustboro Gym

5 Pokémon · highest level Lv 16 · Gym Leader Greta’s own page

	Pokémon	Ability & item	Moves	Base stats
	Impidimp Lv 16 DarkFairy	Ability Prankster Jolly nature	Fake Out Taunt Thunder Wave Covet	HP45Attack45Defense30Sp. Atk55Sp. Def40Speed50Total265
	Stunky Lv 16 PoisonDark	Ability Aftermath Adamant nature	Thief Poison Tail	HP63Attack63Defense47Sp. Atk41Sp. Def41Speed74Total329
	Houndour Lv 16 DarkFire	Ability Unnerve Held item Passho Berry Modest nature	Ember Snarl Thunder Fang	HP45Attack60Defense30Sp. Atk80Sp. Def50Speed65Total330
	Murkrow Lv 16 DarkFlying	Ability Insomnia Modest nature	Air Cutter Snarl Taunt	HP60Attack85Defense42Sp. Atk85Sp. Def42Speed91Total405
	Pawniard Lv 16 DarkSteel	Ability Defiant Held item Oran Berry Jolly nature	Metal Claw Thief Aerial Ace	HP45Attack85Defense70Sp. Atk40Sp. Def40Speed60Total340

★ Lass Tiana — Route 102

2 Pokémon · highest level Lv 6 · Lass Tiana’s own page

	Pokémon	Ability & item	Moves	Base stats
	Venipede Lv 5 BugPoison	Ability Poison Point Hardy nature	Twineedle Poison Sting	HP30Attack45Defense59Sp. Atk30Sp. Def39Speed57Total260
	Houndour Lv 6 DarkFire	Ability Early Bird Hardy nature	Ember Bite	HP45Attack60Defense30Sp. Atk80Sp. Def50Speed65Total330

★ Lady Cindy — Route 104

1 Pokémon · highest level Lv 0 · Lady Cindy’s own page

	Pokémon	Ability & item	Moves	Base stats
	Furfrou level set by your team Normal	Ability Fur Coat Hardy nature	Tackle Bite Howl	HP75Attack80Defense60Sp. Atk65Sp. Def90Speed102Total472

Also fought around here

Everything you can have caught by this checkpoint · Open the interactive guide

It also doesn't say when 23 of its areas open up, so they are listed together in the last part rather than guessed into the story.