The Delta variant was first found in India and, as of last week, has infected 822 people in Thailand.
Social-media posts said five cases of the Delta variant in Phuket were detected on Tuesday and another five on Wednesday.
The provincial health office, however, confirmed that there were indeed 10 confirmed Covid-19 cases in Phuket, but none were of the Delta variant.
As of Tuesday, Phuket had logged 728 Covid-19 cases in the third wave, which was sparked in April.