Ash's Pikachu/History/Sun & Moon series

Pikachu joined Ash and Delia on a vacation to the Alola region in Alola to New Adventure!. On their way to the Pokémon School on Melemele Island, Pikachu and Ash followed a wild into a forest, where the two noticed  riding a. They followed him and arrived at the Pokémon School, where they met some of the school's students as well as and Professor Oak's cousin, Samson Oak. Ash later used Pikachu to battle a trio of s, who were harassing Kiawe, and their trio of, , and. Pikachu was able to dodge their Salandit's attacks with ease and seriously damage them with Quick Attack and Thunderbolt. Kiawe then had his use the Z-Move  which knocked Team Skull's Pokémon out in one shot. That evening, Pikachu and Ash followed, the guardian deity of Melemele Island, who handed Ash a Z-Ring and an Electrium Z. Pikachu remained in Alola with Ash, when he decided to study at the Pokémon School.

In the next episode, Ash's classmates had a surprise welcome party for him, where he and Pikachu participated in several challenges. During their lunch break, Tapu Koko appeared again and stole Ash's hat, prompting Ash and his classmates to follow it. Arriving in a forest, Tapu Koko challenged Ash to a Pokémon battle. Pikachu was overwhelmed by Tapu Koko's fast moves and despite Electric Terrain being created by Tapu Koko's Ability, Pikachu's Thunderbolt didn't faze it. Tapu Koko then tapped Ash's Z-Ring, activating it and allowing Pikachu to perform, which destroyed a large part of the area but also caused Ash's Electrium Z to shatter. Afterwards, Tapu Koko flew off again.

In To Top a Totem!, Pikachu was used in Ash's first island challenge trial in Verdant Cavern. Alongside, he first fought a Yungoos and. The two s showed to be tough opponents, as they were able to use to obstruct Pikachu and Rowlet's sight and movements before hitting them with their attacks. Ash then came up a similar tactic using Rowlet's, allowing Pikachu to knock Gumshoos out with Iron Tail, while Rowlet defeated Yungoos. Afterwards, Pikachu and Rowlet had to face a Gumshoos. This Gumshoos proved to be extremely powerful, being able to endure Pikachu's Thunderbolt and knock him to the ground, after which it defeated Rowlet. After his Electro Ball got redirected by Sand Attack, Pikachu was hit hard once again. Pikachu then used Gumshoos's Sand Attack against it by hiding in the sand while using Quick Attack, allowing him confuse and repeatedly attack Gumshoos before finishing it off with a Thunderbolt. This win earned Ash a Normalium Z.

Pikachu was used as Ash's final Pokémon in his battle against Hala during the Melemele Island grand trial in Trial and Tribulation!. He faced Hala's, who was able to block his attacks using its big hands and hit him afterwards. While repeatedly getting hit by Hariyama's, Pikachu eventually managed to slip past Hariyama and strike it with Thunderbolt. Hariyama, however, was not fazed by this attack and proceeded to use, maximizing its Attack but also halving its health. Pikachu then used Quick Attack in an attempt to dodge Hariyama's Z-Move, but was ultimately hit by the attack. After getting up, Pikachu circled around Hariyama using Quick Attack and managed to knock it off its feet using Iron Tail. Ash used this opportunity to have Pikachu perform, which sent Hariyama flying and knocked it out. Having cleared the Melemele Island grand trial, Ash was rewarded a new Electrium Z.

In A Guardian Rematch!, Ash and Pikachu trained for a rematch against Tapu Koko. The next day, the two were greeted by Tapu Koko again and were challenged to another battle. Unlike their last battle, Pikachu managed get a few hits on the guardian deity, but was eventually struck by its powerful attacks. Ash and Pikachu showed their improvements by performing Gigavolt Havoc, which was this time powerful enough to sent Tapu Koko flying. A clash between Pikachu and Tapu Koko, however, blasted the former off a cliff, prompting Ash to jump after him. The two were saved in time by Tapu Koko, who flew off afterwards.

In The Ol' Raise and Switch!, Professor Kukui tasked everyone with switching their partner Pokémon with somebody else. As a result, Pikachu was given to, whilst Snowy went to Ash. Because of her fear of Pokémon, Lillie decided to have a battle with Hobbes and his to help conquer her fear where despite her lack of battle experience, Lillie was able to defeat Oricorio and was able to touch Pikachu. Ash then proposed a battle against Lillie and Pikachu, to show them how strong he and Snowy had gotten together.

In When Regions Collide!, Ash used Pikachu in his battle against Misty in which he battled her. The two started with a collision of Hydro Pump and Thunderbolt. Pikachu then rushed towards Gyarados and scored a direct hit with Quick Attack, sending Gyarados flying. Pikachu then started charging up Electro Ball as Gyarados used, confusing everyone. Ash told Pikachu to ignore the rain and attack. Gyarados, however, countered with a Rain Dance powered Hurricane, which destroyed the Electro Ball and sent Pikachu flying. Deciding it was time to get serious, Misty revealed her Key Stone and Mega Evolved Gyarados into Mega Gyarados. Gyarados launched a Hydro Pump that destroyed the rock Pikachu was standing on and sent him flying into the water. Not letting up, Gyarados tried to attack Pikachu with Crunch, but was struck by Iron Tail after Pikachu managed to climb onto its body. Gyarados then dove underwater and used Hurricane, creating a cyclone of water around Pikachu. Ash told Pikachu to use Thunderbolt to break it, but failed. Ash soon came up with the idea to have Pikachu run on Thunderbolt's electricity with Quick Attack, allowing Pikachu to escape from the cyclone. The two then preformed their Z-Move, Gigavolt Havoc, which hit Gyarados head on, defeating it and giving Ash the win.

During Ash and his classmates' travels in Ultra Deep Sea to rescue Lusamine in 10,000,000 Reasons to Fight!, Pikachu fought Lusamine, who had been fused with a. Eventually, Pikachu and Ash prepared to perform Gigavolt Havoc, until Ash's Electrium Z mysteriously turned into a Pikashunium Z. This allowed the two to perform for the first time; the Z-Move defeated Nihilego, weakening it enough for Lillie and  to pull Lusamine free from its hold.

In A Battle Hand-Off!, Ash used Pikachu in his trial battle at the, where he battled Team Rocket and. Pikachu was quickly overwhelmed by Mimikyu's barrage of attacks, eventually leaving him open for Mimikyu's Z-Move,. However, Pikachu was able to survive the attack by protecting itself with his newly learned. Using his new move, Pikachu was also able to trap Mimikyu, which allowed him and Ash to perform a Z-Move of their own. Ash's Electrium Z then turned into a Pikashunium Z again, allowing Pikachu to use 10,000,000 Volt Thunderbolt once more and defeat Mimikyu. This allowed Ash to qualify for a chance to challenge Nanu's grand trial.