A total of 32,805 eligible voters registered for advance voting on Saturday, the first day of the registration period from March 25-April 9, the Election Commission said.
The advance voting date has been set for May 7, ahead of the election date May 14.
As of 6pm on Saturday, a total of 32,805 voters registered - 32,600 via the internet and 205 at local registration offices.
Bangkok had the most registrants with 15,202, followed by 1,809 in Chon Buri, 1,147 in Nonthaburi, 1,670 in Pathum Thani and 1,566 in Samut Prakan.
Outside the Kingdom, 4,995 registered for advance voting on Saturday - 4,989 via the internet and six at embassies or consulates.
The highest number of registrants was 709 in London, the United Kingdom, followed by 531 in Canberra and Sydney, Australia.
In China, 285 Thai voters from 10 cities registered, compared to 260 in Taiwan.
In South Korea, 299 voters registered in Seoul, and in Japan 267 registered in Osaka, Tokyo and Fukuoka.
Eligible voters, both inside the country and abroad, can register for advance voting via the Smart Vote application from March 25-April 9.
Those who wish to register for advance voting in their own constituencies can do so through two channels - via local registration offices or by postal mail.
In addition to the first two channels, those who wish to register for advance voting outside their constituencies can also do so via the Smart Vote application of the Provincial Administration Department.