The branch in the Farlington area of Portsmouth will not be allowed to sell alcohol today (Thursday) or on Friday.
The store failed three test purchases to children aged between 14 and 17, police said, though they acknowledged that the retailer was doing "an awful lot" to address the situation. The branch has been visited by test purchase teams on three occasions since being caught and has refused the sale on each occasion.
Sainsbury's opted for the 48-hour closure of its drinks aisles rather than face trial, which could have resulted in a £10,000 fine and a three-month alcohol ban.
A Sainsbury's spokesman said: "Sainsbury's is a responsible retailer. We will be working closely with the local authorities to help prevent such an incident happening again."