Anime:
* Episode 172: "The Legend of Thunder!" (Suicune's first appearance, briefly glimpsed)
* Episode 173: "The Legend of Thunder! (Part 2)" (Suicune makes a more prominent appearance)
* Episode 175: "The Wish of the Lake Guardian!" (Suicune is the main focus of the episode)
* Episode 176: "A Friend in Need!" (Suicune appears briefly)
* Episode 185: "The Ties That Bind!" (Suicune makes a cameo)
* Episode 203: "A Wish for the Future!" (Suicune makes a cameo)
* Episode 263: "The Battle Frontier!" (Suicune is briefly seen in a flashback)
* Episode 403: "Facing the Legendary!" (Suicune is briefly seen in a flashback)
* Episode 772: "The Gathering of Legendary Pokémon!" (Suicune appears alongside the other Legendary Beasts)
Pokemon Chronicles:
* Episode 1: "The Legend of Thunder!" (Suicune is the main focus of the episode)
* Episode 4: "The Wish of the Lake Guardian!" (Suicune is the main focus of the episode)
This list isn't exhaustive, as Suicune may have made cameos or been mentioned in other episodes. However, these are the most notable and significant appearances of the Legendary Pokemon.