Part 6: Beat Clay — Driftveil City Gym, badge 5

Surf (HM03)

Beat Clay — Driftveil City Gym, badge 5 opens 6 areas.

Where to go

1. Chargestone Cave

   Wild: Drilbur 100% · Lv 25-28, Joltik 39% · Lv 25-28, Klink 24% · Lv 26-28, Ferroseed 20% · Lv 26-27 +3 more

2. Relic Passage

   Wild: Drilbur 80% · Lv 16-19, Basculin 70% · Lv 10-30, Marill 60% · Lv 10-30, Poliwag 60% · Lv 40-70 +11 more

3. Route 6

   Wild: Basculin 70% · Lv 10-25, Marill 60% · Lv 10-30, Poliwag 60% · Lv 40-70, Poliwhirl 55% · Lv 40-70 +16 more

4. Mistralton Cave

   Wild: Drilbur 100% · Lv 27-30, Boldore 30% · Lv 27-28, Woobat 30% · Lv 27-28, Aron 20% · Lv 29-30 +1 more

5. Route 7

   Wild: Audino 85% · Lv 30-33, Tranquill 30% · Lv 30-32, Cubchoo 25% · Lv 30-33, Deerling 20% · Lv 30 +8 more

6. Celestial Tower

   Wild: Litwick 100% · Lv 27-30, Elgyem 40% · Lv 30-33, Golbat 20% · Lv 33, Mesprit Lv 65

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

It also doesn't say when 5 of its areas open up, so they are listed together in the last part rather than guessed into the story.