Figures published by payments provider Dojo show that between April 12 and April 29, Portsmouth shoppers spent roughly £15 more than consumers in any other major city.
The average transaction in previously-shut retail stores in the city came to £131.37.
By comparison, an average of £116.47 was spent per transaction in Coventry, ranked second on the list.
Tenth on the list was Blackburn, with an average transaction of £80.65.
According to Dojo, the combination of staycations in Hampshire alongside the quirky vintage of Southsea is allowing the city to thrive and enjoy a summer of spending.