The game will take place in Portugal as both clubs will be on a training camp in the region at the same time. Posh hope to arrange a second friendly while they are abroad.
Posh won’t play any friendlies at home as work on improving their playing surface is prioritised.
This disappoints Posh who fancied landing a big Premier League at home as their usual money-spinning summer tours are not expected to take place.
The Championship fixtures for the 2021-22 season are expected to be released on Thursday, June 24.
That date should be confirmed after this season’s Championship play-offs are completed on May 29. Bournemouth and Swansea take narrow leads into the semi-final, second legs this weekend.
The Championship season will kick off on Saturday, August 7 with the first round of the Carabao Cup set for week commencing August 9.