Public concern and uncertainty swept across the country following Thursday's announcement by the government.
The man was among 26 sailors who arrived in Apia on Friday last week on a repatriation flight from Auckland with more than 250 others.
The government said he was stationed in Europe, adding all the sailors were tested for coronavirus upon arrival at Faleolo Airport.
An initial test at the airport returned a negative result for the coronavirus.
But the second test on Wednesday came back positive, making him Samoa's first suspected case for the virus.