The branch at 17 West Street will open at 1pm on June 17, providing an additional 50 hours of Post Office services a week.
It closed temporarily in August 2020 following the resignation of the postmaster.
Graham Brander, Post Office network provision lead, said: ‘We are delighted to be restoring Post Office service to Portchester as we know how important Post Office services are to a community.’
The opening hours for the Post Office in West Street will be Monday to Saturday, 7am to 7pm, and Sunday, 9am to 5pm.
Two other Post Offices services in the area are located in White Hart Lane.
For more information visit postoffice.co.uk.