The Office of Alcoholic Beverages has announced that the occupants of vehicles of any kind who drink alcohol during travel are subject to six months imprisonment and/or a 60,000 THB fine.
The penalties will also be imposed on drinkers in vehicles parked on sidewalks or shoulders of public roads, including sois, regardless of whether the vehicles are moving, OAB director Samarn Footrakool said.

Passengers of railbased transport who drink are not subject to the penalties. Drinking occupants and drivers will be equally liable for such violations. “The only exceptions under this law are occupants of vehicles parked in front of their homes,” he said.
Some Other Alcohol Rules In Thailand
Since January 1st 2006 Thailand has enforced a law that only allows shops to sell alcohol between 11.00 am.- 2.00 pm. and 5.00 pm.- 2.00 am.

Staff at some stores have difficulty in explaining to foreigners why they cannot be sold alcohol between 2 and 5 PM. Angry outbursts by customers who think they are being singled out are not uncommon. However remember it’s not up to them; it’s the law!

The Election Commission of Thailand bans the sale of alcohol at any retail outlet, and the serving of alcohol in all bars and restaurants during elections. This ban only applies to so-called Type 3 and Type 4 sellers, those who are licensed to sell liquor and spirits in quantities below 10 litres per occasion. Retail shops such as 7-Elevens and Big C supermarkets are put in the same position as wholesalers (being Type 1 and Type 2 sellers) and can only sell in quantities above 10 litres.

The reason given in the text of the relevant Ministerial Regulation is to enhance ”the government’s policies towards controlling the consumption of liquor and tobacco for the benefit of society, in the case of liquor by decreasing the times for retail liquor sales”. Yet the choice of the hours of 2pm to 5pm must have had a more specific purpose than that. One popular school of thought is that it is designed to help prevent underage drinking. Classes typically finish for the day by 2pm, and the theory is that wayward students might then run to the nearest 7-Eleven and start drinking. Yet the ban is in place seven days a week.

Another reason for the ban may simply be that the government is trying to curb all-day ”benders”, or afternoon drinking by people who might be inclined to play hookie from work after lunch with their colleagues.

Legal Drinking Age and Alcohol-Free Zones
Thailand introduced the Alcoholic Beverage Control Act in 2008 , which amended some of Thailand’s previous alcohol laws and increased the drinking age from eighteen to twenty. The Act has specific language making it illegal to sell alcohol to anyone under twenty years old. The Act also set forth laws and penalties for designated areas where alcohol cannot legally be consumed. For example, drinking alcohol is illegal in the following locations: temples or places of worship; infirmaries and pharmacies; public offices; education institutions; petrol stations or petrol station shops and public parks. There are exceptions to many of these locations. For example, if you are attending an authorized banquet at an education institution or public office, or if you are within a temple at which consuming alcohol is part of the worship, then you may legally drink an alcoholic beverage. The penalty for drinking alcohol and one of the aforementioned locations without proper authorization is up to 6 months imprisonment and/or no more than a fine of ten thousand baht.
Selling alcohol to anyone who has previously lost consciousness from drinking is also against the law in Thailand. Additionally, if you are considered intoxicated and provoke an altercation with a law enforcement official, the penalty can be up to one year imprisonment and/or a fine up to twenty thousand THB.