The tourist called police in Uppsala at around 10.30pm on Sunday to explain he had been left inside a Coop grocery store in central parts of the university town and was not able to get out.
The man had gone to the toilet, and when he came out the store was locked and the lights turned off, reports regional newspaper Upsala Nya Tidning.
"He could not get out and called us and tried to explain in shaky English what had happened," police control room officer Daniel Ågren told the newspaper.
Police sent a security guard to the store who was able to let the man out.
"He was rescued and can keep on touristing," said Ågren.