Upvote:1
The US visa expiration date has no bearing on how long you are permitted to stay in the US. This is decided at the border by the immigration officer when you enter the country. Your stay can extend beyond the expiration date of the visa.
Normally on a P1 visa your initial entry should correspond approximately with the dates of the event(s) you are participating in. On a P1 visa you can enter up to 10 days before the start of your petition validity period, and you can leave at most 10 days after the end of the validity period.