Part 2: Beat Roxanne — Rustboro City Gym, badge 1

Beat Roxanne — Rustboro City Gym, badge 1 opens 2 areas.

Where to go

1. Rusturf Tunnel

   Wild: Whismur 100% · Lv 5

2. Route 116

   Wild: Zigzagoon 60% · Lv 4, Nincada 35% · Lv 4, Skitty 5% · Lv 4

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

It also doesn't say when 9 of its areas open up, so they are listed together in the last part rather than guessed into the story.