But it will be a slow rollout, officials say.
The legislation will be implemented starting Thursday, July 1.
Businesses have until April 1, 2022, to comply.
After that they will be fined.
Environmental advocates say Philadelphia uses close to 1 billion single-use plastic bags every year.
The city will use the next nine months as a warning period.
Business owners are encouraged to start phasing out their single-use plastic bag supply now and post signs to notify customers.