An official announcement on Wednesday stated that the province has now heightened preventive measures after the 30-year-old man tested positive.
His wife and two sons have been quarantined at Udon Thani hospital and other relatives are also under 14-day quarantine.
He went with his wife to Samut Sakhon on December 10 and was tested for Covid-19 on December 22.
As many as 500-800 people who might have made contact with him and his family are being screened.
Two locations, including a market in Non Sung sub-district which he visited, were closed, while the schools his sons attended have also been shut until January 8.