When it comes to Pokémon, the elusive and powerful Legendary Pokémon stand out, both for their strength and their importance to the lore of the Pokémon world. While encounters with Legendary Pokémon have become more plentiful over the years, it was still often a big event when one appeared before Ash Ketchum and his friends.
Many of the anime’s biggest episodes feature Legendary Pokémon flexing their power, but Legendaries have also appeared in more low-key episodes, particularly in later series. The best episodes with Legendary Pokémon tend to be the culmination of ongoing story arcs, rather than stand-alone episodes, so the following episodes may be best viewed as part of their appropriate story arcs. Still, even without the added context, many of these episodes are full of epic battles and tremendously strong Pokémon, and are absolutely worth watching for fans of these Legendary Pokémon.
10 Team Rocket Captures Lugia
Episode: Pokémon Gold and Silver, “A Promise is a Promise”
One of the earliest appearances of a Legendary Pokémon being relevant to the plot of a story arc is this one, relatively late in Ash’s Johto adventure. In this episode, a mother and baby Lugia appear, having been captured by Team Rocket, who are using a new machine that amplifies a Pokémon’s power through making it rage. Ash and friends have been taken as well, and must work together to free themselves and Lugia. Once Lugia is free, it brings terror down upon Team Rocket to save its child.
The episode is noteworthy for a few reasons. Of course, this is a rare example of a Legendary Pokémon having reproduced, something that’s not possible in the games. It’s also a different Lugia from the second movie, establishing that Legendary Pokémon are definitely not one-of-a-kind. Besides that, it’s a fun story arc where the broader Team Rocket organization gets to be menacing.
9 Charizard Defeats Articuno
Episode: Pokémon Ruby and Sapphire, “The Symbol Life”
This episode marks the start of Ash’s conquest of the Battle Frontier in Kanto, and he’s up for a heck of a first match, as the Frontier Brain Noland is using the Legendary Pokémon Articuno. Ash chooses to use his Charizard, which has returned from training in the Charicific Valley, but quickly finds that Articuno is prepared to deal with Fire-types. It’s an epic battle between the two flying Pokémon, but Ash eventually emerges victorious, winning his first Frontier Symbol.
This marks the first time that a Legendary Pokémon is defeated by a non-legendary, a major achievement for both Ash and Charizard. Ash would go on to battle other Legendary Pokémon here at the Battle Frontier, and those matches are exciting as well, but there’s just something about that first victory over a Legendary that makes this episode special.
8 Kyogre and Groudon Face Off
Episode: Pokémon Ruby and Sapphire, “The Scuffle of Legends”
Part 2 of a two-parter, this episode finally features Kyogre and Groudon going at it, as Team Aqua launches its plan to increase the size of the oceans. With Archie possessed by the Red Orb, however, he starts to go mad with power and threatens to destroy everything. Pikachu is similarly possessed by the Blue Orb, granting it the power of a Legendary Pokémon. Pikachu and Groudon team up and manage to push Kyogre back. The power of the Orbs is disrupted, however, and Groudon and Kyogre cease fighting.
This episode is the culmination of the Team Aqua and Magma subplot that ran through much of the Hoenn season. While Groudon and Kyogre’s battle could’ve been a bit more exciting, it’s very cool to see Pikachu wield the power of a Legendary. The episode also features Lance and his Red Gyarados, which is a fun bit of continuity.
7 Team Rocket Nearly Destroys Unova
Episode: Pokémon Black and White, “Unova’s Survival Crisis!”
Team Rocket once again attempts to use Legendary Pokémon to aid their plans for conquest, but things go awry very quickly. After taking the Mythical Meloetta that had been traveling with Ash, Giovanni and Team Rocket are able to access an artifact known as the Reveal Glass, giving them control over the Legendary Pokémon, Tornadus, Thundurus, and Landorus. Much like Archie, though, the Reveal Glass begins to affect Giovanni’s mind, pushing him towards destruction.
This is another culmination of a long story arc, but it doesn’t need much context to be enjoyed. Jessie, James, and Meowth inadvertently save the day here by trying to rescue Giovanni, which is a fun twist. Even Giovanni seems a little disturbed by how far he went, and retreats without conflict when he comes to his senses, leaving Meloetta to soothe the rampaging Legendaries.
6 Nebby Evolves into Solgaleo
Episode: Pokémon Sun & Moon, “Revealing the Stuff of Legend!”
Ash has been watching over a mysterious Pokémon nicknamed Nebby for a while, and brings it to the Altar of the Sunne in hopes of encountering the Legendary Pokémon Solgaleo and Lunala, who could help them to retrieve Lillie’s lost mother, Lusamine. Ash is in for a surprise, though, as he finds the Legendary Island Guardians there already, who perform a ritual that causes Nebby to evolve–into the very Solgaleo they were looking for.
This episode does require a fair bit more context from surrounding episodes than most on this list, but seeing Nebby evolve after all the time Ash has spent with it is very exciting. The episode features quite a lot of Legendary Pokémon, with a cameo from Lunala as well. This episode mostly sets up the actual climax of the arc, but it’s noteworthy for Nebby’s evolution alone.
5 A Battle Against the Strongest Legendary
Episode: Pokémon Journeys, “Sword and Shield… The Legends Awaken!”
Chairman Rose has summoned the dangerous Pokémon Eternatus in a bid to ensure Galar has all the energy it could ever need for the future, but unsurprisingly, Eternatus gets out of control in a hurry. Ash defeats Rose in battle using his newly evolved Lucario, and then he and Goh aid Leon in battling Eternatus. Eternatus takes on its Eternamax form, the strongest Legendary ever, and when things look bleak, Zacian and Zamazenta appear to help defeat Eternatus and save the Galar region. Goh even manages to catch it!
This episode is the climax of a 4-part storyline covering the Darkest Day from the Sword and Shield games, featuring the Legendary Pokémon from those games. Some fans dislike the storyline for allowing Goh to catch such a powerful Pokémon, but since he wisely gives it over to Leon for safekeeping, it hardly seems like an issue.
4 Team Galactic Nearly Succeeds
Episode: Pokémon Diamond and Pearl, “The Battle Finale of Legend!”
The climax of the Team Galactic arc sees Dialga and Palkia fall under their control. Aided by Cynthia and Looker, Ash and his friends attempt to put a stop to Team Galactic’s plot to create a new universe. They manage to free the Lake Guardians, Azelf, Uxie, and Mesprit, who each team up with one of our heroes. Using the Legendaries’ power, Ash and friends are able to break the chains controlling Dialga and Palkia, freeing the embodiments of time and space. Cyrus disappears into his new universe alone, but Team Galactic is utterly defeated.
Featuring quite a lot of legendary Pokémon, this episode makes for an exciting conclusion to the Team Galactic arc, mirroring the games. The presence of fan-favorite characters like Cynthia and Looker certainly helps, and it highlights the character strengths of Ash, Brock, and Dawn by aligning them with the Lake Guardians.
3 A Legendary Pokémon’s Gift
Episode: Pokémon Sun & Moon, “Memories in the Mist!”
This episode is quite different from many on this list, as the Legendary Pokémon isn’t the focal point of the episode. Rather, this is a character episode focusing on Mallow, who learns that Tapu Fini has the ability to create a fog that allows people to speak with the dead one more time. Mallow, whose mother passed away when she was young, is initially reluctant to engage, but soon finds herself face to face with her mother once again. After the mist dissipates, Mallow discovers a Shaymin, a Mythical Pokémon said to appear to those who are grateful, which she befriends.
It can be a surprisingly emotional episode, and ties back to one of the saddest episodes of Pokémon ever, with the appearance of the Stoutland that once cared for Ash’s Litten. Mallow’s Shaymin is never officially caught, but does become a recurring figure throughout the rest of Sun & Moon.
2 Ash Battles Tapu Koko at Full Power
Episode: Pokémon Sun & Moon, “From Z to Shining Z!”
After Ash becomes the Alola champion, he faces Professor Kukui in an exhibition match. When Kukui is down to his last Pokémon, Tapu Koko steps in, insisting that he battle Ash with it instead. Tapu Koko even grants Professor Kukui temporary use of its Z-Move, Guardian of Alola. Faced with immense power, Ash and Pikachu use their own Z-Move, and manage to overpower Tapu Koko, securing their reputation as new champions.
This is obviously a major moment for Ash, and for those who’ve watched all of Sun & Moon, Ash finally conquering Tapu Koko is a win that was a long time coming. Much of the series has been about earning Tapu Koko’s respect, after all, and Ash finally manages to impress the Legendary Pokémon. The fight gets pretty crazy as well, as the two Z-Moves clash, and acts as the effective climax of the entire series.
1 Zygarde Completely Destroys the Enemy
Episode: Pokémon XY, “Forming a More Perfect Union!”
The peak of the entire XY anime is the final battle with Team Flare, which lasts for several episodes. This marks the final episode of the battle, and sees the Gym Leaders of Kalos working together with Ash, Alain, and others to defeat Lysandre’s Giant Rock creature. Ash is at his most fearless here, putting himself at great risk to take down Lysandre. After having traveled with the Zygarde core named Squishy, Ash’s companion Bonnie is able to help it achieve its final form, Zygarde Complete, which destroys the rock and Lysandre with its powerful move, Core Enforcer.
The entire story arc is about as epic as the Pokémon anime ever gets, and this conclusion is incredibly exciting. Seeing Zygarde in its Complete form using such a tremendous amount of power gives the often overlooked Legendary some proper respect. This is also one of the few times where a villain is explicitly killed, as Zygarde causes Lysandre to fall into an explosion, sealing his fate. For these reasons, this is certainly the Pokémon anime’s best episode to feature a Legendary Pokémon, and one of the best ever.