Where can I exchange currency for a good rate and get an eSIM card in Bangkok?

For the eSIM, I’d personally buy online before arriving rather than spend arrival time comparing airport kiosks. I’d check which Thai network the plan uses, the data allowance, validity, hotspot support, and whether there’s any speed throttling. For a normal Bangkok trip using Grab, Maps, messaging and social media, you may not need unlimited data. Full disclosure: I’m building SIMLIT, so I’m biased — we support Thailand. If you tell me how long you’re staying and roughly how much data you normally use, I’m happy to help estimate what size plan makes sense. For cash exchange, the airport basement exchange counters are worth comparing when you arrive, then you can compare again in the city if you’re exchanging a larger amount.