Bar and kitchen Rapscallions, in Osborne Road, Southsea, will be run by the Swan family and general manager Fahren Smith.
Bosses behind the business say they will sell ‘the largest selection of rum in Portsmouth’.
The venue is set to provide nine famous cocktails named after legendary pirates of old, as well as a Scandal’s cocktail list offering the classics.
For dining in, food will be based on home ports, and homemade pies will come in from the family's other business, The Red Lion, in Southwick.
Rapscallions’ owner, Daniel Swan, will run the new venture with his father, Gary Swan and brother, Calvin Swan.
The staff plan to bring in another menu later on based on favourite pirate ports around the world, but say the opening menu will be ‘food from your home port’.
Daniel said: ‘Some homemade pies are coming in from one of our other businesses like fish and chips and scampi to start initially.
‘Later on, we're going to develop a menu from all the favourite pirate ports from around the world.'
The build's interior was ‘pirate themed already when we got it,’ added Daniel.
The venue is at the former Wave Maiden pub.
‘It's got a barrel bar in it, and it’s quite old.
‘We’ve gone for rum being the main theme because we don't think there's anything like that in Portsmouth at the moment,' he said.
‘There are no rum bars here that mix pirates and rum, so it's a cool pirate, not a cheesy pirate. It’s more Pirates of the Caribbean, not Pirate Pete’s is the famous way I can say it.’
The Rapscallions launch day will open for invite-only on Friday, July 30 and staff will also pick two people who have liked their Facebook page to attend the VIP opening.
The rum and cocktail bar will open to the public the following day, and customers will be able to make bookings.
The restaurant’s opening times are 4pm to 1am Monday to Thursday, 12 pm to 2am on Fridays and Saturdays, and 12 pm to 12 am on Sundays.
Rapscallion’s Facebook page tells customers to expect hearty food, amazing cocktails, bar shows, Portsmouth’s first bottomless Rumtini brunch, and plenty of sea shanty singing.