Ash's Buizel was caught by Dawn but was traded to Ash because the Buizel preferred battles over contests.
Buizel gained a reputation for being a very powerful Pokemon and proved capable of defeating Dawn's Piplup, Zoey's Glameow and Ash's Pikachu. However because he focused on strength, Buizel was unprepared for contest moves and Dawn managed to capture him.
While Ash and Dawn where preparing for their gym and contest battles, Buizel was showing more interest in what Ash was doing, than the contest, while Aipom was doing the same with Dawn's training. Ash and Dawn traded Aipom and Buizel.
In DP068 Buizel battled Maylene's Lucario and learned Water Pulse. After blowing a hole in the ceiling when his Water Pulse collided with Lucario's Aura Sphere, it started raining and Buizel's Swift Swim was activated. The battle ended in a draw. Later Buizel competed in the Wallace Cup losing to a Lanturn in the top 8.
Ash used Buizel against Paul's Gastrodon and won with Ice Punch. He also battled Paul's Drapion who was attacked with a powerful Pin Missile but Buizel was able to do use Water Gun Counter Shield and dodged Cross Poison. While in the air, Buizel used SonicBoom but Drapion blocked it and ensnared Buizel with its tail claw. Buizel broke free by inflating his floatation sac and then blasting Drapion with Water Gun but Drapion launched Toxic Spikes while Buizel was still in the air. As soon as he landed Buizel was poisoned by Toxic Spikes and Drapion finished him with Pin Missile, resulting in Buizel being knocked out.
Kiyotaka Furushima, who voices Ash's Sinnoh rival, Paul in the original Japanese version, voices Ash's Buziel in both the Japanese and English-language versions of the anime.
Buziel is Ash's only Water Pokemon to know an Ice-type move.