Not in the wild but he battles them a lot.
In the original series it's "The Battling Eevee Brothers"
episode 553
the second episode.
bls
4
episode 24
In the first episode of season 6.
The episode in which Ash meets Paul is the episode that is titled "When Pokémon Worlds Collide," it is the 3rd episode in the Sinnoh region and its overall episode number is Episode 471.
Ash meets Brock in episode 5 of season 1, Showdown in Pewter City.
Ash meets Riley in the episode "Saving the World from Ruins!" which is the episode no 7 in Pokemon galactic battles.
In the episode ''Get the Show on the Road'' season 6.
23