Does my baby need a visa if she is under two years old in Thailand?

Every foreigner visiting Thailand need a legal stay which they get based on passport at immigration checkpoint.

This could be the short time tourist entries, like Visa on Arrival, Visa Exempt Entry, Tourist Visa or the long term visa, like Non Immigrant or DTV.

There is NO minimum age or even maximum age.

The story that some parents love to hear, is that by Thai law, children (Thai and foreign) can not get a fine until the age of 15 years, that is why you see children doing exercise after being stopped at traffic stops. NO FINE but exercise.

Some people advice you to ignore the law as no fine means you are allowed to break the law, your insurance company sees it different and same as schools.

No you should get your baby a visa. Our under two year old also has a DTV (dependant). You'll be travelling in and out of Thailand possibly several times a year and having the visa saves a lot of questions.