Despite being the long-running Pokémon anime's central hero, Ash isn't what most fans would call a great trainer. Admittedly, the series' protagonist has a lot of heart, and he genuinely cares for his partners. These are both important parts of being a trainer. However, he's been known to make many questionable strategic decisions.
He finally recently won a League Championship after a couple of decades trapped at the age of ten. Maybe he would have won one sooner if he stopped casting aside some very powerful and loyal Pokémon. Ash has released several of his Pokémon during his career as a trainer, and while not all fans might agree with his decisions, they've all been memorable milestones.
Updated on December 13th, 2022 by Chelsea Steele: Throughout Ash Ketchum's journey, he's encountered and captured many different Pokémon. However, not all of them end up staying on his team for good, and some have even been released. Whether they return to the wild or simply go down a different path, several of Ash's Pokémon have been released over the years. This list has been updated to include even more Pokémon that have parted ways with Ash during his travels.
13 Haunter Stayed With Sabrina After Ash Won The Marsh Badge
"Haunter vs. Kadabra" - Episode 24 of Pokémon: Indigo League
During Ash's quest to obtain the Marsh badge in Saffron City, he found that Gym Leader Sabrina was nearly impossible to defeat. However, he finally got the upper hand after catching a mischievous Haunter that agreed to help him win the battle.
While it caused more harm than help with its pranks, Haunter managed to bring a smile to Sabrina's stoic face, ultimately leading Ash to victory. Since the two had bonded, Ash then released Haunter and left it with Sabrina so the two could live together happily as friends.
12 Larvitar Eventually Returned To Its Mother
"Mother of All Battles" - Episode 55 of Pokémon: Master Quest
Though Ash technically never caught Larvitar, it was still under his care for quite some time, and the two became incredibly close during their time together. After hatching Larvitar in an egg, Ash and the gang kept it in order to protect the new Pokémon from poachers.
However, once the danger subsided, Ash returned his new friend to Mt. Silver, where it was reunited with its mother. Though Larvitar is no longer a part of the team, it still has a close bond with Ash and the two have remained friends ever since.
11 Nebby Parts Ways With Ash After Becoming A Solgaleo
"10,000,000 Reasons to Fight!" - Episode 54 of Pokémon: Sun & Moon
When Ash and his friends first encounter Nebby, it's still just a young Cosmog. Much like with Larvitar, Nebby technically hasn't been caught by Ash and isn't his official Pokémon. Nevertheless, Ash cares for it just like the rest of his team, and the two become fast friends.
With Ash and Lillie's care and guidance, Nebby is able to evolve over time, and eventually becomes a strong and majestic Solgaleo. Once Nebby reaches its final evolution, it no longer needs their protection and is able to strike out on its own. Instead of catching Nebby and keeping it with him, Ash parts ways with his friend and lets it roam free as a wild Pokémon.
10 Pikachu Almost Gets Left With A Colony Of Wild Pikachu
"Pikachu's Goodbye" - Episode 39 of Pokémon: Indigo League
Pikachu is separated from Ash for a few minutes at most. This happens very early in the series, when the gang stumbles upon a colony of wild Pikachu. Ash's Pikachu saves another small Pikachu from a raging river and is accepted into the colony as a hero.
After seeing how happy Pikachu is, Ash decides to leave him behind for his own good. Of course, Pikachu doesn't want to part ways with his best friend, and the two are reunited before the episode ends.
9 Charizard Stays Behind To Train On Its Own
"Charizard's Burning Ambitions" - Episode 18 of Pokémon: The Johto Journeys
Charizard is one of the most powerful Pokémon Ash has ever trained. So powerful, in fact, that its abilities as a battler outstripped Ash's abilities as its trainer. As a result, Charizard became unruly and prone to lighting Ash on fire. By the time Ash is challenging the Johto League, Charizard is able to wipe the floor with most low-level battlers.
Eventually, they were able to mend their relationship. In "Charizard's Burning Ambitions," they visit a valley full of powerful wild Charizard, and Ash convinces his long-time friend to stay there and grow stronger. Charizard has returned a few times to lend Ash a hand, but he still returns to his new home.
8 Poipole Eventually Had To Return Home
"Securing the Future!" - Episode 90 of Pokémon: Sun & Moon
Poipole was an incredibly affectionate member of Ash's team in the Alola season. Through its drawings, Poipole expressed on multiple occasions that it truly cared for Ash and considered him and his other team members to be family.
However, they had to part because Poipole had been sent to Alola through an Ultra Wormhole on a mission to bring light back to its homeland to save its hive of other Poipole and Naganadel. Ash actually ends up releasing this Pokémon twice: once as Poipole and once after it had evolved into Nagandel and briefly rejoined his team.
7 Primeape Stayed Behind To Train
"The Punchy Pokémon" - Episode 29 of Pokémon: Indigo League
Ash met Primeape when it was a mischievous Mankey. They were first at odds after Mankey stole Ash's hat. Ash caught it after Team Rocket made it so mad that it evolved into a Primeape. In the episode "The Punchy Pokémon," Ash meets a man training for a Fighting-type Pokémon tournament and entered Primeape.
They grew closer over the course of the tournament and Primeape won, but it decided it wanted to stay and train with the other Fighting Pokémon. It's possible Ash could return to Kanto one day and reunite with Primeape.
6 Goodra Returned Home After Becoming Stronger
"Beyond the Rainbow!" - Episode 22 of Pokémon: XY Kalos Quest
Goodra joined Ash's team as a Goomy and had a surprisingly traumatic backstory. It had seen its wetland home invaded by an army of Bug- and Fairy-type Pokémon, led by an intimidating Florges.
The battle caused Goomy to flee, and it later fell into Ash's lap. After training with Ash and growing much stronger, Goodra wanted to return to its swampy homeland and make it a safe place for its Goomy friends and relations.
5 Pidgeot Stays Behind To Protect Its Flock
"Pallet Party Panic" - Episode 1 of Pokémon: Adventures in the Orange Islands
Pidgeotto was the second Pokémon Ash ever caught himself and was with him for a long time. They part ways in "Pallet Party Panic," when the gang returns to Pallet Town and finds the local Pidgey flocks being tormented by a familiar foe, the Spearow that Ash tried to catch on his very first day as a trainer. It had since evolved into a Fearow and was leading a gang of wild Spearow.
Pidgeotto actually evolved into a Pidgeot in this episode out of desperation to save his fellow birds. Ash released Pidgeot so it could continue to protect its friends. He promised to come back for it after his adventures on the Orange Islands, but he has yet to do so after all this time.
4 Squirtle Went Back To Rejoin The Squirtle Squad
"The Fire-ing Squad" - Episode 31 of Pokémon: The Johto Journeys
Ash won Squirtle's loyalty by protecting it from Team Rocket before it had even officially joined the team. Prior to meeting Ash, Squirtle was the leader of a gang of abandoned Squirtles called the Squirtle Squad.
In the episode "The Fire-ing Squad," the Squirtle Squad enters a firefighting competition. Ash's Squirtle led his old squad to victory in the contest, and Ash realized that Squirtle's gang needed it more than Ash did. Squirtle's returned to lend a hand since then but is no longer officially part of Ash's team.
3 Lapras Returns Home To Its Family
"Viva Las Lapras" - Episode 33 of Pokémon: Adventures in the Orange Islands
Ash befriended Lapras when it was very young. It had been separated from its family and washed up on the beach, where Ash found three children tormenting it. Ash and Pikachu chased them off and promised to reunite Lapras with its family.
Since it was a young Pokémon, it wasn't used much for battling and was mostly used as transportation around the Orange Islands. In "Viva Las Lapras," they discover Lapras' herd and were able to reunite it with its mother.
2 Butterfree & Ash Part Ways After It Falls In Love
"Bye-Bye Butterfree" - Episode 21 of Pokémon: Indigo League
The very first Pokémon Ash ever caught was also the first he ever released in one of the most memorably heartbreaking episodes of the original series. Butterfree joined Ash's team as a Caterpie and suffered from low self-esteem due to Misty hating Bug Pokémon.
They part ways in "Bye-Bye Butterfree" when Butterfree finds a flock of other Butterfree during mating season. It tries desperately to woo a shiny pink Butterfree, but only succeeds after it rescues the flock from Team Rocket. Fans like to believe that the two of them are still very happy together.
1 Greninja Leaves Ash's Side In Order To Save The Kalos Region
"Beyond the Rainbow!" - Episode 22 of Pokémon: XY Kalos Quest
Greninja was one of Ash's closest and most powerful partners. The two shared such a close bond that it was possible for Greninja to take on another more powerful form dubbed "Ash-Greninja." It rivaled the power of Mega-Evolved Pokémon, but it had one downside - Ash shared any pain or injury suffered by Greninja in this form.
It turned out that Greninja had a special ability to sense the roots of the Giant Rock that almost destroyed the Kalos region. The two then parted ways so Greninja could help Zygarde eliminate the remaining roots in the very same episode Ash released Goodra.