What is the best Thai SIM card for expats on holiday that offers good data for apps like WhatsApp?

When choosing a Thai SIM card for holiday use, many users recommend AIS for its excellent coverage across the country, especially in rural areas. True is considered good as well, particularly in urban locations, while DTAC is praised for its performance on islands and remote areas. All three major carriers offer prepaid plans that are similarly priced and have comparable coverage in major cities. Users looking for eSIM options can find availability with all major carriers. Buying a tourist SIM typically provides nationwide coverage without additional costs for calls or texts between different regions.