Part 8: Beat Tate & Liza — Mossdeep City Gym, badge 7
Waterfall opens up in Sootopolis City.
Beat Tate & Liza — Mossdeep City Gym, badge 7 opens 13 areas. There are 150 trainers standing in them. The fights at this checkpoint are Gym Leader Glacia [Permanent Hail], Triathlete Sharon & Expert Auron, Cooltrainer Athena, and 12 more.
Where to go
Route 125
Wild: Wooper 70%, Quagsire 60%, Bruxish 40%, Buneary 25% +5 more
Trainers: ★ Triathlete Sharon & Expert Auron, ★ Triathlete Sharon & Expert Auron, Sailor Ernest, Sailor Ernest, Bird Keeper Presley, Bird Keeper Presley +8 more
Pick up: Blue Shard, Sticky Barb, Lopunnite
Route 127
Wild: Tentacool 70%, Tentacruel 60%, Quagsire 40%, Wooper 40% +6 more
Trainers: ★ Cooltrainer Athena, ★ Cooltrainer Athena, ★ Twin Sister Roxanne, ★ Twin Sister Roxanne, Bug Catcher Roger, Bug Catcher Roger +12 more
Pick up: TM06 Toxic, TM76 Stealth Rock, Grip Claw, Aggronite
Route 126
Wild: Basculin 70%, Tentacool 40%, Tentacruel 40%
Trainers: ★ Pokéfan Leonardo & Pokéfan Isobel, ★ Pokéfan Leonardo & Pokéfan Isobel, Swimmer Nikki, Swimmer Nikki, Psychic Dean, Psychic Dean +8 more
Pick up: Flame Orb
Route 128
Wild: Carvanha 70%, Sharpedo 60%, Tentacool 40%, Swellow 30% +1 more
Trainers: ★ Cooltrainer Alexa, ★ Cooltrainer Alexa, Cooltrainer Ruben, Cooltrainer Ruben, Triathlete Isaiah, Triathlete Isaiah +8 more
Pick up: TM89 U-Turn
Seafloor Cavern
Wild: Spheal 100%, Walrein 60%, Sealeo 30%, Beartic 20% +6 more
Trainers: ★ Steven's Team [Tag Partner], ★ Steven's Team [Tag Partner], ★ Aqua Admin Shelly & Aqua Grunt 5 [Rain], ★ Aqua Admin Shelly & Aqua Grunt 5 [Rain], ★ Aqua Leader Archie [Rain, Back to Back Battle 1/2], ★ Aqua Leader Archie [Rain, Back to Back Battle 1/2] +10 more
Pick up: TM29 Psychic, Focus Band, Aerodactylite
Sootopolis City
Wild: Magikarp 70%, Tentacool 40%
Pick up: TM08 Bulk Up, TM12 Taunt, HM07 Waterfall, Assault Vest, Safety Goggles
Move tutor: Flare Blitz, Head Smash, Secret Sword, Leaf Storm, Pursuit, Recover, Perish Song, Mist, Rage Powder, Baton Pass
Route 129
Wild: Slowpoke 70%, Slowbro 60%, Feebas 40%, Ludicolo 10%
Trainers: ★ Triathlete Allison, ★ Triathlete Allison, Swimmer Reed, Swimmer Reed, Triathlete Chase, Triathlete Chase +4 more
Pick up: TM64 Explosion
Route 130
Wild: Wimpod 70%, Golisopod 60%, Slowpoke 40%, Barbaracle 30% +7 more
Trainers: ★ Bug Catcher Rodney, ★ Bug Catcher Rodney, Triathlete Katie, Triathlete Katie, Swimmer Santiago, Swimmer Santiago
Pick up: TM61 Will-O-Wisp, Scizorite
Route 131
Wild: Spheal 70%, Basculin 60%, Lapras 60%, Slowpoke 40% +1 more
Trainers: ★ Lass Susie, ★ Lass Susie, Swimmer Kevin, Swimmer Kevin, Triathlete Talia, Triathlete Talia +8 more
Pick up: Slowbronite
Sootopolis City Gym
Trainers: ★ Gym Leader Glacia [Permanent Hail] Lv 69, ★ Gym Leader Glacia [Permanent Hail] Lv 67, Lass Andrea, Lass Andrea, Pokefan Annika, Pokefan Annika +16 more
Mossdeep Space Center
Trainers: ★ Magma Leader Maxie & Magma Admin Tabitha [Tag Battle with Steven], ★ Magma Admin Tabitha & Magma Leader Maxie [Tag Battle with Steven]
Trick House Puzzle 6
Trainers: Ranger Sophia, Ranger Sophia, Ranger Sebastian, Ranger Sebastian, Guitarist Benny, Guitarist Benny
Mossdeep City Space Center
Trainers: Magma Grunt 1, Magma Grunt 1, Magma Grunt 2, Magma Grunt 2, Magma Grunt 3, Magma Grunt 3 +8 more
★ Gym Leader Glacia [Permanent Hail] — Sootopolis City Gym
| Pokémon | Ability & item | Moves | Base stats | |
|---|---|---|---|---|
 | Frosmoth Lv 68 IceBug | Ability Ice Scales Held item Focus Sash Timid nature · EVs 252HP/252Spe | Aurora Veil Defog Hidden Power Fire Blizzard | HP70Attack65Defense60Sp. Atk125Sp. Def90Speed65Total475 |
 | Primarina Lv 68 WaterFairy | Ability Liquid Voice Held item Leftovers Modest nature · EVs 252HP/252Sp.Atk | Hyper Voice Blizzard Moonblast Charm | HP80Attack74Defense74Sp. Atk126Sp. Def116Speed60Total530 |
 | Mamoswine Lv 68 IceGround | Ability Thick Fat Held item Choice Scarf Jolly nature · EVs 252Atk/252Spe | Earthquake Icicle Crash Knock Off Ice Shard | HP110Attack130Defense80Sp. Atk70Sp. Def60Speed80Total530 |
 | Sandslash (Alola) Lv 68 IceSteel | Ability Slush Rush Held item Chople Berry Adamant nature · EVs 252Atk/252Spe | Icicle Crash Iron Head Aqua Tail Swords Dance | HP75Attack100Defense120Sp. Atk25Sp. Def65Speed65Total450 |
 | Weavile Lv 68 DarkIce | Ability Pressure Held item Life Orb Jolly nature · EVs 252Atk/252Spe | Swords Dance Knock Off Icicle Crash Ice Shard | HP70Attack120Defense65Sp. Atk45Sp. Def85Speed125Total510 |
 | Abomasnow Lv 69 GrassIce | Ability Inverted Scales Held item Abomasite Quiet nature · EVs 252HP/252Sp.Atk | Blizzard Giga Drain Earth Power Ice Shard | HP90Attack92Defense75Sp. Atk92Sp. Def85Speed60Total494 |
★ Triathlete Sharon & Expert Auron — Route 125
| Pokémon | Ability & item | Moves | Base stats | |
|---|---|---|---|---|
 | Magmortar level set by your team Fire | Ability Flame Body Held item Assault Vest Modest nature · EVs 200HP/200Sp.Atk | Fire Blast Heat Wave Thunderbolt Taunt | HP75Attack95Defense67Sp. Atk125Sp. Def95Speed83Total540 |
 | Slurpuff level set by your team Fairy | Ability Unburden Held item Focus Sash Adamant nature · EVs 148Atk/252Spe | Play Rough Drain Punch Helping Hand Endeavor | HP82Attack80Defense86Sp. Atk85Sp. Def75Speed72Total480 |
 | Lopunny level set by your team Normal | Ability Limber/Scrappy Held item Lopunnite Adamant nature · EVs 148Atk/252Spe | Fake Out High Jump Kick Quick Attack Return | HP65Attack76Defense84Sp. Atk54Sp. Def96Speed105Total480 |
 | Garchomp level set by your team DragonGround | Ability Rough Skin Held item Rocky Helmet Jolly nature · EVs 148HP/252Spe | Stealth Rock Swords Dance Outrage Iron Tail | HP108Attack130Defense95Sp. Atk80Sp. Def85Speed102Total600 |
 | Whiscash level set by your team WaterGround | Ability Adaptability Held item Choice Band Adamant nature · EVs 200HP/200Atk | Liquidation Stomping Tantrum Wave Crash Earthquake | HP110Attack102Defense79Sp. Atk76Sp. Def71Speed60Total498 |
 | Amoonguss level set by your team GrassPoison | Ability Effect Spore Held item Kee Berry Calm nature · EVs 200HP/200Sp.Def | Spore Synthesis Rage Powder Giga Drain | HP114Attack85Defense70Sp. Atk85Sp. Def80Speed30Total464 |
★ Cooltrainer Athena — Route 127
| Pokémon | Ability & item | Moves | Base stats | |
|---|---|---|---|---|
 | Jellicent level set by your team WaterGhost | Ability Water Absorb Held item Room Service Calm nature · EVs 200HP /200Sp.Def | Trick Room Strength Sap Will-o-Wisp Scald | HP100Attack60Defense70Sp. Atk85Sp. Def105Speed60Total480 |
 | Hippowdon level set by your team Ground | Ability Sand Stream Held item Liechi Berry Adamant nature · EVs 200HP/200Atk | Stealth Rock Yawn Earthquake Slack Off | HP108Attack112Defense118Sp. Atk68Sp. Def72Speed47Total525 |
 | Honchkrow level set by your team DarkFlying | Ability Moxie Held item Expert Belt Brave nature · EVs 200HP/200Atk | Brave Bird Sucker Punch Heat Wave Taunt | HP100Attack125Defense52Sp. Atk105Sp. Def52Speed71Total505 |
 | Ninetales level set by your team Fire | Ability Flash Fire Held item Life Orb Timid nature · EVs 148Sp.Atk/252Spe | Nasty Plot Fire Blast Energy Ball Extrasensory | HP73Attack76Defense75Sp. Atk81Sp. Def100Speed100Total505 |
 | Aggron level set by your team SteelRock | Ability Sturdy/Filter Held item Aggronite Careful nature · EVs 200HP/200Sp.Def | Heavy Slam Curse Sleep Talk Rest | HP70Attack110Defense180Sp. Atk60Sp. Def60Speed50Total530 |
Also fought around here
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.