Under the new law, a customer who is served a bottle of beer at 1:59 p.m. but continues drinking on the premises until 2:05 p.m. would be in violation and be fined, Bangkok Post reported.
The new regulation has drawn criticism from both locals and foreign media outlets, which have warned travelers visiting Thailand to exercise caution, Nation Thailand reported.
Foreign tourists flooded social media with criticism of the rule, calling it "unreasonable and restrictive" and some said they would avoid Thailand in favor of regional destinations with more relaxed alcohol rules.
Thailand's long-standing alcohol sale ban, which typically lasts from 2 p.m. to 5 p.m. at most retail outlets and supermarkets, has been in place for over five decades.
In Thailand, where Buddhism is the main religion, practitioners and monks follow the Five Precepts, which include abstaining from alcohol and intoxicants to promote mindfulness and avoid heedlessness.