What are the best options for purchasing a long-term SIM card and data plan in Bangkok?

In Bangkok, several options are available for purchasing long-term SIM cards and data plans. Many users recommend visiting AIS stores, which are commonly found in major shopping malls, as well as 7-Eleven outlets. Other providers like DTAC and True also have similar offerings, with competitive pricing and services. Notably, some users have found that purchasing SIM cards online via platforms like Shopee can offer substantial savings, especially for plans with significant data allowances. AIS is frequently mentioned for having better coverage in remote areas, while True has been noted for its affordability and reliability.