The patient came to Singapore from the UK on December 6 and had been quarantined on arrival before testing positive on December 8.
Singapore has been conducting viral genomic sequencing for confirmed COVID-19 cases who arrived from Europe recently.
The country's health ministry emphasised that there was no evidence that the new B117 variant is circulating in the community.
All of the patient's close contacts had been placed on quarantine but tested negative at the end of their quarantine period.
Long-term pass holders and short-term visitors who have been to the UK in the last 14 days have not been allowed to enter or transit through Singapore since Wednesday.


Afghanistan says Pakistan strikes kill and injure dozens
Police officer killed, dozens injured in bomb explosions in Ukraine's Lviv
Trump pivots to new 15% global tariff after Supreme Court setback
Hong Kong plans to buy homes devastated in deadly high-rise fire
US Supreme Court strikes down Trump's global tariffs
