Vivacity Premier Fitness and the Regional Pool and Leisure Centre will reopen on Monday, August 17 – but it has been confirmed that Lido will not open this year.
Jack Hunt, Bushfield, Hampton and Werrington leisure centres will open before the end of September (exact dates to be confirmed).
The Athletics Arena will also remain closed at this time.
Vivacity said: "Memberships remains frozen. We will honour the freeze in membership payments for the first month and the extension to annual memberships for the period of time the gyms have remained closed. Peterborough City Council fully support this decision.
"We appreciate that some of our customers will not be ready to return to the gym just yet, in this case we are happy to continue to freeze your membership until the end of December – please advise us by Monday, September 7.
"If you have already written to us regarding your membership, all of these enquiries will be dealt with once our gyms reopen. If you have cancelled your membership during the period of closure this will be actioned once our venues reopen. No payments will be taken in the interim."
Set activity sessions for gym, swim and exercise classes will be implemented with a maximum number of people to maintain social distance when using the facilities.
Changing rooms will not be open at the gym except for those taking part in swimming and aqua class sessions, and showers will also be out of use.
If you're interested in joining the gym, you are still able to do so online. For more information, click here.