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.


Tanzania's Hassan declared landslide winner in election marred by violence
Vietnam's ancient town Hoi An works to restore tourism after devastating floods
Indian temple stampede kills nine, injures several
Turkey to host Gaza meeting amid ceasefire concerns
Tanzania opposition says hundreds killed in vote protests
Turkey sentences 11 people to life in prison over ski resort hotel fire
China sends its youngest astronaut to 'Heavenly Palace' space station
Israel launches more strikes on Gaza overnight, testing fragile truce
