Should I get eSIM or buy a SIM at Bangkok airport? +
eSIM wins for convenience. Suvarnabhumi airport SIM counters often have 30-60 minute queues. With eSIM, you buy online in advance, activate via QR before landing, and walk straight through customs with internet already working.
Does Thailand eSIM work on the islands? +
Yes. Phuket, Koh Samui, Koh Phangan, Koh Tao, Koh Lanta, and Koh Chang all have good AIS 4G coverage. Very remote areas or jungle interiors may have limited signal, but beaches, towns, and resorts are all well covered.
Can I top up Thailand eSIM while in the country? +
Yes. Most plans allow online top-ups through the provider's app or website. Find hotel WiFi, purchase additional data, and you're connected again immediately β no need to visit a physical store.
Will Thailand eSIM work on sleeper trains? +
AIS network covers Thailand's main train routes including the Bangkok-Chiang Mai overnight line and Bangkok-Surat Thani (for Koh Samui ferry). Coverage is good through cities and towns, with some signal gaps in rural sections.