Location: Hau'oli City

Your first encounter with Team Skull is in Hau'oli City. When you go to the Marina to find Ilima, the Trial Captain, you will be accosted by two Team Skull Grunts who want to take the Pokémon from Ilima. Ilima stands firm in his refusal and you battle the grunt. They leave saying nobody needs to know about their failure.

Location: Berry Fields

As you travel through Route 2, a Delibird will come up to you and lead you to the Berry Fields, where there appears to be some sort of commotion. When there, you'll find the same grunts as before and are trying to harass the Berry Master into giving him all of his Berries. Once again, you stop them from managing to succeed.

Location: Verdant Cavern

During the first Island Trial, the two Team Skull grunts will interrupt as revenge for you getting in their way. They will once again challenge you. Once defeated, however, they will then block various holes where Gumshoos/Raticate will come out of, trying to sabotage your trial.

Location: Route 5

The next encounter with Team Skull is on Akala Island with a different pair of grunts. These grunts don't battle you but do in fact speak to Gladion, who they yell at for stopping them from stealing the Totem Pokémon. They mention how despite their boss liking Gladion, he will never be a member of Team Skull.

Location: Route 6

When on Route 6, approaching the Royal Avenue, you will see two Team Skull grunts harassing a trainer with Mudsdale and Drifloon. It appears the grunts are the same ones you dealt with on Melemele Island, and their defeat caused them to be exiled to Akala Island. Here, they are trying to take a Drifloon. The trainer introduces herself as Hapu and requests your help in dispatching the Grunts.

Location: Diglett's Tunnel

When travelling through the Diglett's Tunnel, you will encounter two employees who will greet you. They will inform you that Team Skull had been riling up Pokémon in the area and that Team Skull often interfere with Pokémon. Soon after, you and Hau will meet two Grunts who quickly challenge you to a battle

Location: Memorial Hill

As you get to Memorial Hill, you will encounter two Aether Foundation employees battling with two Team Skull grunts. The Aether Foundation employees request your help in dealing with Team Skull so you battle the grunts. After that, you soon meet Plumeria who mentions that Gladion mentioned you. She says about how she's like a big sister who keeps Team Skull together and challenges you for picking on her brothers and sisters.

Team Skull Admin Plumeria	Golbat	Salandit
Battle Type Items	Level 25	Level 26
	Attacks: Air Cutter Confuse Ray	Attacks: Flame Burst Double Slap Poison Gas
	Hold Item: No Item	Hold Item: No Item

Location: Route 10

The next encounter with Team Skull is a very minor encounter in Route 10 where you confront the two grunts waiting for a bus. Defeat them and they mention returning to living large in the mansion.

Location: Malie Gardens

When you go to Malie Gardens, you will see Kukui facing off against two grunts. When you go to help him, someone interrupts. They introduce themself as Guzma, the leader of Team Skull. Guzma has history with Kukui, stating how they were both rejected to being Trial Captains and that the League he's building is irrelevant as everyone knows he's the strongest trainer in Alola. He spots you and your Z-Ring and questions you as to why you bother with it. He then decides to challenge you to destroy things that Kukui loves

Team Skull Boss Guzma	Golisopod	Ariados
Battle Type Items	Level 31	Level 30
	Attacks: Swords Dance Razor Shell First Impression	Attacks: Fell Stinger Sucker Punch Shadow Sneak Infestation
	Hold Item: No Item	Hold Item: No Item

Location: Route 15

The next encounter with Team Skull is a brief one. As you approach the Aether House, a Team Skull grunt will question Lillie about what's in the bag, since it was moving. You'll battle him and then he'll then quickly run off.

Location: Route 15

After completing Acerola's trial, when you return to the Aether House, you will interrupt Plumeria and two Skull Grunts who weren't expecting you back so soon. They quickly challenge you.

Team Skull Admin Plumeria	Golbat	Salazzle
Battle Type Items	Level 34	Level 35
	Attacks: Air Cutter Confuse Ray Poison Fang	Attacks: Flame Burst Double Slap Toxic Dragon Rage
	Hold Item: No Item	Hold Item: No Item

After defeating, you then learn that Team Skull stole a child's Yungoos as a message for you to come alone without backup to their base in Po Town to meet their boss.

Location: Route 17

The next encounter with Team Skull is in Route 17. As you are trying to go to Po Town, they then accuse you of coming to mock them because they never were able to complete the Island Challenge. Defeat all the grunts in Route 17 and they will leave, without you being able to get in. Then, a mysterious man will appear and let you in.

Location: Po Town

Po Town is a unique town in that it has been completely overrun by Team Skull. There's grafitti everywhere and they even have control of the Pokémon Center, where they will charge you to heal your Pokémon. You need to navigate various paths to get through Po Town, defeating grunts along the way, in order to make it to the Shady House in the back.

Location: Shady House

In the Shady House, you need to make it up to Guzma's room. To do so, you have to find three passwords scattered across the house. One is Golisopod, another is Tapu Cocoa and the other is Beat Up. You also need to say "No" when asked if you are sure about the passwords. Defeat all the grunts along the way. When you get to Guzma's room, he yells at you to just care about your Pokémon and stay out of his business. He then challenges you.

Team Skull Boss Guzma	Golisopod	Ariados
Battle Type Items	Level 37	Level 36
	Attacks: Swords Dance Razor Shell First Impression	Attacks: Fell Stinger Sucker Punch Shadow Sneak Infestation
	Hold Item: No Item	Hold Item: No Item

Defeat him and you'll get the Buginium Z and he'll order his underlings to give Yungoos back. They then mostly evacuate Po Town. However, you quickly learn that this was a distraction and that Plumeria and some grunts have kidnapped Lillie. Gladion suggests going to the Aether Paradise.

Location: Aether Paradise

In the Aether Foundation, as you battle through the Aether employees, when you come to the end you will find that Team Skull has been working with the Aether Foundation to hunt for the Pokémon that Lillie stole, Cosmog. You need to battle through the grunts after Gladion rushes through to attack Guzma. With Guzma having defeated Gladion and chastising him for failing, with him saying how he crushed Gladion, you then have to face Guzma yourself.

Team Skull Boss Guzma	Golisopod	Ariados	Masquerain	Pinsir
Battle Type Items	Level 41	Level 40	Level 40	Level 40
	Attacks: Swords Dance Razor Shell First Impression	Attacks: Fell Stinger Sucker Punch Shadow Sneak	Attacks: Air Slash Bug Buzz	Attacks: Double Hit Brick Break X-Scissor
	Hold Item: No Item	Hold Item: No Item	Hold Item: No Item	Hold Item: No Item

Defeat him and he will eventually join you up when you're trying to stop Lusamine, however when Lusamine goes into the Ultra Wormhole, Guzma follows her in.

Location: Ancient Poni Path

As you go through Poni Island in an attempt to revive Solgaleo/Lunala and retrieve Lusamine & Guzma, you get stopped by a group of grunts who challenge you. Defeat them and Plumeria will appear. She asks if you're really able to get Guzma back, and then apologies for what she did to Lillie, giving you the Poisonium Z.

Location: Ultra Space

When you go to the Ultra Space to retrieve Lusamine, you will find Guzma there. Guzma will explain how he tried to capture the Ultra Beast, but it instead took control of its mind and now he knows fear, and that Lusamine is too far gone. He then states his desire to leave the place.

Location: Route 13, Po Town

Team Skull still has a presence across the Alola Region after completing the game. They will still be in Po Town, though the grunts in the Pokémon Center will sell you a special Team Skull tanktop. Plumeria can also be found out of Team Skull clothing and in regular clothing in Route 13, with other former Team Skull Grunts.

Location: Route 2, Hau'oli City

When you go to the house in Route 2, you will find out that it was Guzma's house and he is in it, with the Skull logo scratched off of his clothing. He will say he has unfinished business with you and will meet you on the beach. His mother will mention that she never believed the bad things people said about him. When on the Hau'oli City Beachfront, he will say that despite disbanding Team Skull, he will never change and will show you what destruction is like, in human form.

Pokémon Trainer Guzma	Golisopod	Ariados	Pinsir	Masquerain	Scizor
Battle Type Items	Level 63	Level 63	Level 63	Level 63	Level 63
	Attacks: Sucker Punch Waterfall First Impression	Attacks: Fell Stinger Sucker Punch Toxic Thread Cross Poison	Attacks: Guillotine Storm Throw X-Scissor Stone Edge	Attacks: Air Slash Bug Buzz Ice Beam Energy Ball	Attacks: X-Scissor Iron Head Night Slash Bullet Punch
	Hold Item: No Item	Hold Item: No Item	Hold Item: No Item	Hold Item: No Item	Hold Item: No Item

When defeated, Hala will appear and explain to Guzma that he misses the true meaning of battling. He will then offer to mentor Guzma. Guzma goes to leave, but gives you a Dawn Stone, which he insists is not an apology.

Location: Pokémon League

Details:
No longer a member of Team Skull, Plumeria will be convinced by Nanu and Molyane to challenge the Elite Four and so appears as one of the characters who will appear to challenge your title.

Pokémon Trainer Plumeria	Gengar	Muk	Crobat	Toxapex	Salazzle
Battle Type Items	Level 61	Level 61	Level 61	Level 61	Level 61
	Attacks: Shadow Ball Dark Pulse Sludge Bomb Dazzling Gleam	Attacks: Venoshock Brick Break Toxic Rock Slide	Attacks: Leech Life Fly Poison Fang Protect	Attacks: Liquidation Baneful Bunker Recover Poison Jab	Attacks: Sludge Bomb Flamethrower Dragon Pulse Protect
	Hold Item: No Item	Hold Item: No Item	Hold Item: No Item	Hold Item: No Item	Hold Item: Poisonium Z