They were tested on day seven of their quarantine, when they were confirmed to have contracted the virus.
The patient is still in mandatory isolation and is said to be doing well.
Pictured: The positive case was picked up in a day seven test.
“The identification of this second case further demonstrates that our border controls, testing regimes and track and trace protocols are working,” said Director of Public Health, Dr Nicola Brink.
“Again, it is important that the community are reassured that we have robust systems in place to identify and manage cases of covid-19.”
This is the second covid-19 case to be confirmed in Guernsey recently, after the island went months without any positive results.
However, the first positive patient has now recovered, meaning there is only one known active case in the Bailiwick.
Pictured top: Dr Nicola Brink.