Sealeo was used in the Double Battle round of Juan's Gym battle against Ash, fighting alongside Juan's Sealeo against Pikachu and Snorunt. Pikachu started off with Thunderbolt, but Juan's Seaking protected Sealeo by using Horn Drill, thus redirecting the attack back to Pikachu. Pikachu tried using Thunder, but Seaking redirected the attack, causing Snorunt to be electrocuted as well. Sealeo launched Blizzard, which freezed Pikachu, though Snorunt used Icy Wind and created an ice boulder. Seaking and Sealeo launched Hyper Beam and Aurora Beam to shatter the ice, which allowed Pikachu and Snorunt to mount an attack. While Pikachu evaded Sealeo's Aurora Beam, Snorunt got defeated by Seaking's Hyper Beam. Ash sent Corphish out, while Sealeo and Seaking dived into the pool. Pikachu dodged Sealeo's Aurora Beam, while Corphish grabbed Seaking's horn, who tried using Horn Attack. Seaking repelled Corphish with Horn Drill, but was defeated by Pikachu's Iron Tail.
Before arriving to Slateport City for May's Grand Festival, she and Ash remembered their past adventures so far. Ash recalled facing Juan, whose Seaking and Sealeo were used in the Double Battle. Pikachu dodged Sealeo's Aurora Beam, but Snorunt took Seaking's Hyper Beam attack. Soon after, Pikachu defeated Seaking with Iron Tail and Corphish defeated Sealeo with Crabhammer.