I got to my Airbnb in Thailand and the wifi was just awful, like 2 Mbps on a good day. I had a video call with a client in 24 hours and started to panic. Went to a 7-Eleven and grabbed a tourist SIM from AIS for about 400 baht, which is like $11. Set up a hotspot on my phone and instantly had a solid 30 Mbps connection. I did that whole call from a coffee shop patio without a single drop. It was so simple but I almost didn't do it because I thought the Airbnb wifi would be fine. Now I budget for a local data plan in my first two days anywhere. What's the best carrier you've found for data in Southeast Asia?