The mandate goes into effect at the start of the November season. Those not eligible for the shot, like children, can present a negative test.
"Our industry has been so shaken in the past year and a half, and our best chance of going forward is for people to feel safe when they come," said Emily Zeck, managing director of the Philadelphia Theatre Company.
The Philadelphia Theatre Company at the Suzanne Roberts Theatre is one of 32 in the region to collectively sign on to this new audience policy.
New York's Broadway announced in the summer that audiences would need proof of vaccination. Just last week, President Joe Biden implored sporting venues to do the same.
"It makes it easier for everyone, especially for theatergoers, that they can know that these are the rules, they don't have to check various websites," said LaNeshe Miller-White, Executive Director of Theatre Philadelphia
Some venues are even using the app Bindle to streamline vaccine verification.
The hope is to get the majority of the region's theatres on the app and normalize this new theatre experience.