Can I change my monthly swimming activity challenge?

iPhone alone does not generate or support monthly fitness challenges for swimming at all.

Those monthly challenges (including the “swimming” one) only exist in the Activity app on Apple Watch. Without a watch, there is no official monthly challenge for the iPhone to change, edit, or skip.

Swimming requires Apple Watch’s water-lock sensors and workout metrics. The iPhone has no way to measure swimming.

Apple won't penalize you, and all other badges, goals, Streaks, and Rings still count normally.

geeta296 wrote:

Ok I made a mistake I want to change my monthly challenge on my Apple Watch

The only mistake was by by Apple, setting you challenge without any watch workout history.