In Making Battles in the Sand!, Goh first encountered Trapinch when he and Ash were investigating a Sandstorm that had hit Mauville City. Goh consults his Pokédex, learning that Trapinch digs bowl-shaped pits to trap and hunt prey. Goh decides he will have to catch Trapinch to save the people. A standard throw failed, but he managed to catch the Ant Pit Pokémon with a curveball.
In Absol Absolved!, Goh sent Trapinch out and had it use Dig to investigate underground in an oddly snowy portion of Mt. Chimney. However, it quickly resurfaced, shuddering from the cold, and Goh promptly recalled it.
In Big Brother to the Rescue!, Goh used Trapinch, along with other Pokémon in Cerise Park, to create a pond for Grimer to live in without dirtying the park's water stream.
In Heroes Unite!, Trapinch joined the rest of Goh's Pokémon at the lab to celebrate their Trainer's return from the last mission of Project Mew. In This Could be the Start of Something Big!, it attended a surprise party hosted by the Lab members commemorating Goh and Ash's departure.