A navy personnel patrol in the Chiang Khong area of Chiang Rai intercepted six Chinese nationals after they crossed over into Thailand from Laos.
They were all men aged 17 to 25.
The border between the countries remains closed during the pandemic.
The men claimed they were on a shopping trip in Thailand.
They did not have proper papers and are now in the custody of immigration.
Naew Na said that such an incursion was the latest example of the Covid-19 regulations being flouted.