Location: Iki Town

You will first encounter Hau soon after you have obtained your Starter Pokémon. He is eager to meet the new trainer who has come to the region and will challenge you to a battle instantly. He has chosen the Starter Pokémon that is weak to yours, which he received from Hala, his grandfather.

Pokémon Trainer Hau	Popplio
Battle Type Items	Level 5
	Attacks: Pound Water Gun Growl
	Hold Item: No Item
Rowlet Chosen

Pokémon Trainer Hau	Rowlet
Battle Type Items	Level 5
	Attacks: Tackle Leafage Growl
	Hold Item: No Item
Litten Chosen

Pokémon Trainer Hau	Litten
Battle Type Items	Level 5
	Attacks: Scratch Ember Growl
	Hold Item: No Item
Popplio Chosen

Location: Iki Town

The next encounter with Hau is also in Iki Town. During this encounter, you will enter the special festival to celebrate Tapu Koko and the festival must conclude with a strong Pokémon battle, and it has fallen to you and Hau to have the battle.

Pokémon Trainer Hau	Pichu	Popplio
Battle Type Items	Level 6	Level 7
	Attacks: Thunder Shock Charm Tail Whip	Attacks: Pound Water Gun Growl
	Hold Item: No Item	Hold Item: No Item
Rowlet Chosen

Pokémon Trainer Hau	Pichu	Rowlet
Battle Type Items	Level 6	Level 7
	Attacks: Thunder Shock Charm Tail Whip	Attacks: Tackle Leafage Growl
	Hold Item: No Item	Hold Item: No Item
Litten Chosen

Pokémon Trainer Hau	Pichu	Litten
Battle Type Items	Level 6	Level 7
	Attacks: Thunder Shock Charm Tail Whip	Attacks: Scratch Ember Growl
	Hold Item: No Item	Hold Item: No Item
Popplio Chosen

Location: Hau'oli City

The next encounter with Hau continues on from the Festival and has Hau come and get you so that you, he and Lillie can explore the nearby city, Hau'oli City. He will go to the Malasada Restaurant.

Location: Route 2

Your next encounter with Hau is another short one where he will simply show you to the nearby Pokémon Center and give you 3 Revives.

Location: Route 3

After you have retrieved Cosmog from the Melemele Meadow for Lillie, when you leave the area, you will bump into Hau. Hau has just finished the completion of his trial and challenges you to a battle.

Pokémon Trainer Hau	Pikachu	Popplio
Battle Type Items	Level 13	Level 14
	Attacks: Growl Play Nice Quick Attack Electro Ball	Attacks: Water Gun Growl Disarming Voice Baby-Doll Eyes
	Hold Item: No Item	Hold Item: No Item
Rowlet Chosen

Pokémon Trainer Hau	Pikachu	Rowlet
Battle Type Items	Level 13	Level 14
	Attacks: Growl Play Nice Quick Attack Electro Ball	Attacks: Leafage Growl Peck Astonish
	Hold Item: No Item	Hold Item: No Item
Litten Chosen

Pokémon Trainer Hau	Pikachu	Litten
Battle Type Items	Level 13	Level 14
	Attacks: Growl Play Nice Quick Attack Electro Ball	Attacks: Ember Growl Lick Leer
	Hold Item: No Item	Hold Item: No Item
Popplio Chosen

After defeating him, he will note at how you're both getting stronger and queries if he will be able to beat Hala, his grandfather and then joins you in Iki Town as you defeat Hala.

Location: Hau'oli City - Akala Island

Joining you on your journey further, Hau will take the boat to Akala Island with you, Kukui and Lillie. When you arrive, Hau will wonder about the kind of Malasada that they make in Akala Island and so heads off to see while Lillie goes off to go shopping herself.

Location: Paniola Town

When you reach Paniola Town, Hau will appear and will challenge you to a battle. With him having also been gifted with a Z-Ring, Hau is eager to test out his new strategies using his Z-Moves.

Pokémon Trainer Hau	Pikachu	Brionne
Battle Type Items	Level 16	Level 17
		Torrent
	Attacks: Electro Ball Quick Attack	Attacks: Aqua Jet Disarming Voice Pound
	Hold Item: No Item	Hold Item: Normalium Z
Rowlet Chosen

Pokémon Trainer Hau	Pikachu	Dartrix
Battle Type Items	Level 16	Level 17
	Attacks: Electro Ball Quick Attack	Attacks: Razor Leaf Peck Tackle
	Hold Item: No Item	Hold Item: Normalium Z
Litten Chosen

Pokémon Trainer Hau	Pikachu	Torracat
Battle Type Items	Level 16	Level 17
	Attacks: Electro Ball Quick Attack	Attacks: Fire Fang Lick Scratch
	Hold Item: No Item	Hold Item: Normalium Z
Popplio Chosen

Location: Route 5

The next encounter with Hau is another short one. When you reach the Pokémon Center in Route 5, you will see Hau and Gladion, and learn that Gladion has just defeated Hau in battle.

Location: Royal Avenue

Your next encounter with Hau is in the Battle Royal Dome in Royal Avenue. He goes there to watch matches, but when he sees the Masked Royal challenge you to a battle, he insists on joining the matchup in a Battle Royal with you, Masked Royal, and Gladion

Pokémon Trainer Hau	Brionne
Battle Type Items	Level 19
	Torrent
	Attacks: Aqua Jet Disarming Voice Pound
	Hold Item: Normalium Z
Rowlet Chosen

Pokémon Trainer Hau	Dartrix
Battle Type Items	Level 19
	Attacks: Razor Leaf Peck Tackle
	Hold Item: Normalium Z
Litten Chosen

Pokémon Trainer Hau	Torracat
Battle Type Items	Level 19
	Attacks: Fire Fang Lick Scratch
	Hold Item: Normalium Z
Popplio Chosen

Location: Diglett's Tunnel

When you go through the Diglett's Tunnel to reach Konikoni City, you will find Team Skull and the Aether Foundation. The Aether Foundation give you a warning about Team Skull, but when you encounter Team Skull, you and Hau team up to battle the grunts

Location: Ruins of Life - Aether Paradise

After defeating Olivia in the Ruins of Life, you will bump into Hala who will mention that he, like you, has been invited to go to the Aether Paradise. You join him on the boat there and are taken up to the Conservation Area where you meet Lusamine. Lusamine explains the Aether Paradise and Hau is impressed by the fact she is 40. However, soon after that, an Ultra Wormhole opens up and an Ultra Beast comes through, and you have to defeat it.

Location: Malie City

After the incident in the Aether Paradise, Hau will join you on the boat to Ula'ula Island. He remarks at how different it is from Melemele and Akala Islands but then suggests that you two have a battle.

Pokémon Trainer Hau	Raichu	Flareon	Brionne
Battle Type Items	Level 28	Level 28	Level 29
	Attacks: Electro Ball Quick Attack Psychic	Attacks: Fire Fang Quick Attack	Attacks: Bubble Beam Disarming Voice
	Hold Item: No Item	Hold Item: No Item	Hold Item: Waterium Z
Rowlet Chosen

Pokémon Trainer Hau	Raichu	Vaporeon	Dartrix
Battle Type Items	Level 28	Level 28	Level 29
	Attacks: Electro Ball Quick Attack Psychic	Attacks: Water Pulse Quick Attack	Attacks: Razor Leaf Pluck
	Hold Item: No Item	Hold Item: No Item	Hold Item: Grassium Z
Litten Chosen

Pokémon Trainer Hau	Raichu	Leafeon	Torracat
Battle Type Items	Level 28	Level 28	Level 29
	Attacks: Electro Ball Quick Attack Psychic	Attacks: Giga Drain Quick Attack	Attacks: Fire Fang Bite
	Hold Item: No Item	Hold Item: No Item	Hold Item: Firium Z
Popplio Chosen

After defeating him, he will join you in visiting the Malie Gardens where you meet up with Lillie and Kukui once more.

Location: Route 13

When you reach Route 13, Hau will come and say hello to you. He will congratulate you on completing Sophocles' trial and give you some Max Potion. Soon after that, Gladion appears and questions if you have heard of the Pokémon Cosmog. Hau accidentally lets slip that you have and you both are asked by Gladion to protect Cosmog from Team Skull at all costs.

Location: Aether House

When you get to the Aether House, Hau will appear but the two of you are quickly challenged by a group of preschoolers. After defeating them, the preschoolers will be all over Hau.

Location: Aether House

After completing Acerola's trial in Route 14, when you return to the Aether House, you will find that Team Skull are there and hunting for Cosmog. Hau teams up with you and Acerola in taking on the Team Skull grunts while you take on Plumeria. Team Skull have stolen the children's Yungoos and Hau is angered by this. However, he stays there while you go to Po Town, without backup.

Location: Aether House - Aether Paradise

After Lillie has been kidnapped by Team Skull, then Hau decides to join you and Gladion on a trip to the Aether Paradise in order to find Lillie. In the Aether Paradise, you, Gladion & Hau battle through the various Aether employees in a bid to rescue Lillie. This requires you to go to the secret laboratories in the basement of the building. However, the lift won't go down so you need to go up where you battle with Faba, with Gladion by your side. Soon after that, Wicke appears and indicates that she has history with Gladion, calling him master. Going down to the basement, he asks you not to enter the Secret Laboratory A, but to go to Secret Laboratory B. He will join you in Multi Battles against Aether Foundation employees

Pokémon Trainer Hau	Raichu	Flareon	Primarina
Battle Type Items	Level 38	Level 38	Level 39
	Attacks: Thunderbolt Quick Attack Psychic	Attacks: Fire Fang Quick Attack	Attacks: Sparkling Aria Disarming Voice
	Hold Item: No Item	Hold Item: No Item	Hold Item: Waterium Z
Rowlet Chosen

Pokémon Trainer Hau	Raichu	Vaporeon	Decidueye
Battle Type Items	Level 38	Level 38	Level 39
	Attacks: Electro Ball Quick Attack Psychic	Attacks: Water Pulse Quick Attack	Attacks: Razor Leaf Spirit Shackle
	Hold Item: No Item	Hold Item: No Item	Hold Item: Grassium Z
Litten Chosen

Pokémon Trainer Hau	Raichu	Leafeon	Incineroar
Battle Type Items	Level 38	Level 38	Level 39
	Attacks: Electro Ball Quick Attack Psychic	Attacks: Giga Drain Quick Attack	Attacks: Fire Fang Darkest Lariat
	Hold Item: No Item	Hold Item: No Item	Hold Item: Firium Z
Popplio Chosen

Location: Aether House - Aether Paradise

As you get up to the end of the Paradise in order to stop Lusamine, Hau will soon come up and help. However, as an Ultra Beast comes through the Ultra Wormhole, things take a turn for the worse so Gladion suggests he takes on Type: Null while Hau takes on Guzma and you take on Lusamine.

After that situation, Hau will appear, shocked by Lillie's change of appearance, and will maintain about how he wasn't strong enough to protect people and save Pokémon on his own since he keeps being rescued by you and your Pokémon.

Location: Mount Lanakila

The next encounter with Hau comes much later in the game, as you climb Mount Lanakila to enter the Pokémon League. He states that since the Aether Paradise incident, he went off and passed all his trials, and even trained with Ilmia so that he could be even stronger. He felt it was time to take on the Pokémon League so rushed there as fast as he could. He challenges you to a battle to determine who will be the first person to challenge the Alola Pokémon League

Pokémon Trainer Hau	Raichu	Flareon	Komala	Primarina
Battle Type Items	Level 53	Level 53	Level 53	Level 54
	Attacks: Thunderbolt Quick Attack Psychic Focus Blast	Attacks: Flare Blitz Quick Attack Charm Baby-Doll Eyes	Attacks: Wood Hammer Sucker Punch Earthquake Shadow Claw	Attacks: Sparkling Aria Moonblast Hyper Voice
	Hold Item: No Item	Hold Item: No Item	Hold Item: No Item	Hold Item: Waterium Z
Rowlet Chosen

Pokémon Trainer Hau	Raichu	Vaporeon	Komala	Decidueye
Battle Type Items	Level 53	Level 53	Level 53	Level 54
	Attacks: Thunderbolt Quick Attack Psychic Focus Blast	Attacks: Hydro Pump Quick Attack Charm Baby-Doll Eyes	Attacks: Wood Hammer Sucker Punch Earthquake Shadow Claw	Attacks: Spirit Shackle Leaf Blade Smack Down
	Hold Item: No Item	Hold Item: No Item	Hold Item: No Item	Hold Item: Grassium Z
Litten Chosen

Pokémon Trainer Hau	Raichu	Leafeon	Komala	Incineroar
Battle Type Items	Level 53	Level 53	Level 53	Level 54
	Attacks: Thunderbolt Quick Attack Psychic Focus Blast	Attacks: Leaf Blade Quick Attack Charm Baby-Doll Eyes	Attacks: Wood Hammer Sucker Punch Earthquake Shadow Claw	Attacks: Darkest Lariat Flare Blitz Earthquake
	Hold Item: No Item	Hold Item: No Item	Hold Item: No Item	Hold Item: Firium Z
Popplio Chosen

Location: Iki Town, Route 1, Hau'oli City

The next encounter with Hau is in the credits. He will join everyone in a festival in Iki Town in order to celebrate you becoming the first Alola Region Champion. However, the next day, he rushes to your house and informs you that Lillie is leaving the region and you go to Hau'oli City in order to say your goodbyes. Hau is saddened by the leaving of his friend.

After that, Hau will come back to your house and give you two Z Crystals, for the two Starter Pokémon you didn't pick and tell you that he heard about the Battle Tree in Poni Island, a place filled with strong trainers that he wishes to challenge.

Location: Pokémon League

Details:
Your rival and friend, Hau, has also gone through the Island Challenge and defeated the Elite Four, wanting a rematch from all of the matches he has had with you and intends to become the Alola Region Champion. His team varies based on your starter Pokémon.

Pokémon Trainer Hau	Raichu	Flareon	Komala	Crabominable	Primarina
Battle Type Items	Level 63	Level 63	Level 63	Level 63	Level 63
	Attacks: Thunderbolt Quick Attack Psychic Focus Blast	Attacks: Flare Blitz Quick Attack Charm Baby-Doll Eyes	Attacks: Wood Hammer Sucker Punch Earthquake Shadow Claw	Attacks: Close Combat Ice Hammer Stone Edge Brutal Swing	Attacks: Sparkling Aria Moonblast Hyper Voice
	Hold Item: No Item	Hold Item: No Item	Hold Item: No Item	Hold Item: No Item	Hold Item: Waterium Z
Rowlet Chosen

Pokémon Trainer Hau	Raichu	Vaporeon	Komala	Crabominable	Decidueye
Battle Type Items	Level 63	Level 63	Level 63	Level 63	Level 63
	Attacks: Thunderbolt Quick Attack Psychic Focus Blast	Attacks: Hydro Pump Quick Attack Charm Baby-Doll Eyes	Attacks: Wood Hammer Sucker Punch Earthquake Shadow Claw	Attacks: Close Combat Ice Hammer Stone Edge Brutal Swing	Attacks: Spirit Shackle Leaf Blade Smack Down
	Hold Item: No Item	Hold Item: No Item	Hold Item: No Item	Hold Item: No Item	Hold Item: Grassium Z
Litten Chosen

Pokémon Trainer Hau	Raichu	Leafeon	Komala	Crabominable	Incineroar
Battle Type Items	Level 63	Level 63	Level 63	Level 63	Level 63
	Attacks: Thunderbolt Quick Attack Psychic Focus Blast	Attacks: Leaf Blade Quick Attack Charm Baby-Doll Eyes	Attacks: Wood Hammer Sucker Punch Earthquake Shadow Claw	Attacks: Close Combat Ice Hammer Stone Edge Brutal Swing	Attacks: Darkest Lariat Flare Blitz Earthquake
	Hold Item: No Item	Hold Item: No Item	Hold Item: No Item	Hold Item: No Item	Hold Item: Firium Z
Popplio Chosen