Throughout most of the anime series Sonic X, Tails mirrors his game role in various stories and game adaptations, though he often plays a smaller role in the series due to the presence of Chris Thorndyke. He quickly befriends fellow inventor Chuck Thorndyke, who built the X-Tornado jet with him. In a tournament for a Chaos Emerald, Tails shows that he is stronger than he looks, but gets defeated by Rouge the Bat.
In the third season of Sonic X, Tails is the captain of the Blue Typhoon, and over the series develops leadership skills. Tails has a crush on Cosmo, a plant-like female alien introduced during this season. Cosmo starts to show signs of affection towards Tails as the season progresses. Their relationship is confirmed when they fall into a love trap placed by Amy that was meant to catch Sonic. He emotionally broke down in tears at the conclusion when Cosmo asked him to kill her to defeat the Metarex, but kept one of the seeds she released.