Pokémon Horizonshas just revealed its next season, and though attention is placed on the newaged-up designs forHorizonsprotagonists Liko and Roy,the existence of a timeskip implies that the series might have also aged up Ash as well. Nothing is confirmed at this time, but if Ash has indeed aged, that would be a huge step forward for his character and would no doubt be a big deal for fans of the series who have been watching him for decades.
The poster forHorizons’next season, titledMega Voltage, showcases an apparently older Liko and Roy. While they were around 13 throughoutHorizons, they are apparently going to be either 15 or 16 in the new season. An image spread in the Japanese magazine Corocoro confirms the time skip.

Liko and her friends have grown up and are now going on an adventure with their partner Pokemon. What on earth happened? Liko and the others are growing up! The main characters, Liko and Roy, have grown up and become older. A story of the future beings…?!
Given thatHorizonsappears to take place in the samePokémoncontinuity as Ash, this suggests that, along with Liko and Roy, Ash will have aged too.

Why Pokemon Potentially Aging Ash Up Would Be So Surprising
The Anime’s Staff Has Previously Said Ash Would Never Age
Though whatAsh’s age should be throughout thePokémonanimeis a topic of fierce debate among the series' fans, canonically,Ash has been 10 throughout the entirety of his 1200+ episode run. Despite many classic Pokémon fans wanting to see Ash age,Pokémon’sproducers have stated that, should Ash appear again, he would still be 10. This is part of what makes the decision to age-up Liko and Roy so interesting.
By moving thePokémonanime’s world forward a handful of years, that naturally raises the question of what this means for Ash. IfPokemon Horizonstakes place either after or concurrent to Ash’s final seasonTo Be A Master, as many fans would naturally assume, then Ash would have to be older as of Mega Voltage. Unfortunately, though, even if Ash is technically older, there is no guarantee that fans will ever get to see an older design for the iconic hero.

Pokémon Horizons Has Been Very Careful Not To Mention Ash
So There Is Some Doubt About If He’ll Appear
For a variety of reasons,Ash has yet to appear in or even be referenced byPokémon Horizons. The new anime series has been very careful to avoid referencing Ash, even having Liko and Roy only go up against gym leaders that Ash never met. Ash might be iconic, but having him tag along with Liko and Roy or be a presence in the new series would risk taking the focus away from the new characters and putting it on an old favorite.
Given this undoubtedly deliberate attempt at avoiding even the shadow of Ash, there is a distinct possibility thatPokémon Horizonsfelt comfortable aging up Liko and Roy because it never had plans of having them interact with Ash. If that were the case, andHorizonsavoids Ash altogether, then the next time fans see him could be pre-timeskip.
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The other (more humorous) possibility is that Ash does appear inHorizonsand his age just isn’t addressed. He’ll undoubtedly sport a new design the next time fans see him, and the art style ofHorizonsis malleable enough that it wouldn’t be unreasonable to see a design for Ash that could easily pass for 10 or 13.
Fans Should Remain Optimistic About Ash’s Potential Return For Horizons
Fan Demand Means He’ll Likely Appear At Some Point
Pokémon Horizonshas ran for almost two years now, so it’s safe to say that Liko and Roy are more than established as their own characters. Given this and the intense fan demand to see Ash again, it’s probable thatHorizons' cast will get to interact with Ash at some point. Whether that involves him traveling with the duo, or if it will be more of a chance encounter in a movie remain to be seen.
The big question then will be how he’ll appear. Unfortunately for fans, thePokémonanime hasn’t always been the best about maintaining its continuity, as evidenced by the fact that Ash is still 10 years old after starring in more than 1200 episodes of the series. So even though Ash probably should be at least 13 or even 14 by the time ofMega Voltage, that’s no promise that he will be. Regardless of what the series does with Ash though, it still seems likely that the hero will reappear at some point inPokémonHorizons,it’s just a matter of when.