Specialty: Fighting-type

Details:
After completing Ilmia's challenge, when you return to Iki Town, Hala will challenge you to a battle. Defeat him and you'll get the stamp for your Trainer Passport which allows traded Pokémon up to Level 35 to obey, the Fightingium Z Crystal and he will give you access to the Rider Pager.

Island Kahuna Hala	Mankey	Makuhita	Crabrawler
Battle Type Items	Level 14	Level 14	Level 15
	Attacks: Karate Chop Pursuit Focus Energy	Attacks: Arm Thrust Sand Attack Fake Out	Attacks: Pursuit Power-Up Punch Leer
	Hold Item: No Item	Hold Item: No Item	Hold Item: Fightinium Z

Specialty: Rock-type

Details:
After completing the three Island Trials on Akala Island, Lillie will ask for you to take her to the Ruins of Hope. When there, Olivia will challenge you to the battle for the Grand Trial. Defeat her and you'll get the stamp for your Trainer Passport which allows traded Pokémon up to Level 50 to obey, and the Rockium Z Crystal.

Island Kahuna Olivia	Nosepass	Boldore	Lycanroc
Battle Type Items	Level 26	Level 26	Level 27
	Attacks: Rock Slide Spark Thunder Wave	Attacks: Rock Blast Mud-Slap Headbutt	Attacks: Bite Rock Throw
	Hold Item: No Item	Hold Item: No Item	Hold Item: Rockium Z

Specialty: Dark-type

Details:
After completing the two Island Trials on Ula'ula Island, and facing off against Team Skull in Po Town, then Nanu will introduce himself after helping you briefly. As Lillie gets kidnapped and you, Gladion & Hau head to the Aether Foundation to rescue her, Nanu will inform you that he is the Kahuna of Ula'ula island and challenge you to a battle. Defeat him and you will receive the Darkium Z Crystal and the Trainer Passport stamp that allows for Pokémon up to Level 65 to obey.

Island Kahuna Nanu	Sableye	Krokorok	Persian
Battle Type Items	Level 38	Level 38	Level 39
	Attacks: Power Gem Shadow Ball Fake Out	Attacks: Crunch Assurance Swagger Earthquake	Attacks: Power Gem Fake Out Dark Pulse
	Hold Item: No Item	Hold Item: No Item	Hold Item: Darkinium Z

Specialty: Ground-type

Details:
The final Grand Trial is done a bit differently. When you reach Poni Island, you will discover that there is no Kahuna on the island. The previous one, Hapu's grandfather, passed recently and Tapu Fini has yet to choose a successor. However, as you need to the Kahuna's help, Hapu goes to the Ruins of Hope to request a Kahuna be chosen and becomes the Kahuna. She finally battles you in front of Vast Poni Canyon.

Island Kahuna Hapu	Dugtrio	Gastrodon	Flygon	Mudsdale
Battle Type Items	Level 47	Level 47	Level 47	Level 48
	Attacks: Iron Head Earthquake Sucker Punch Sandstorm	Attacks: Muddy Water Mud Bomb Recover	Attacks: Earth Power Dragon Breath	Attacks: Heavy Slam Earthquake Double Kick Counter
	Hold Item: No Item	Hold Item: No Item	Hold Item: No Item	Hold Item: Groundium Z