The ribbon will be cut on the new store in Southsea’s Albert Road on Saturday, April 15.
It is being run by Premier Coffee, a franchise partner of Costa.
The plans for the store in the old Laundry Land unit drew criticism from residents in February with 60 per cent of News readers rejecting the store’s opening in an online poll.
Manager of the shop Jenni Speight said: ‘The new Costa in Albert Road will become a focal point for people visiting the area to come and experience great coffee in a friendly and relaxed environment.
‘The whole team is looking forward to welcoming the people of Southsea to our new Costa, which we hope will quickly become a key part of the local community.’
Councillor David Fuller, the Lord Mayor of Portsmouth, will cut the ribbon on the new store from 10am.
The new store has created eight jobs and will be open seven days a week. Staff plan to work with community groups and charities.
Ahead of the store’s opening 35,000 buy-one-get-one-free vouchers have been distributed in and around Southsea for customers.