Thailand uses the same power plug socket as Canada & US. No need to buy adapter
One cool thing I loved about Thailand was not needing a power plug adapter for travellers coming from Canada and the US
The same 3-pronged power plug we have from back home worked everywhere I went in Thailand. The 2-pronged power plug from north america also worked as well
The voltage is higher at 220 versus 110 back home but it's not a problem for most electronics these days as they all have voltage converter inside. I didn't bring any converter and my phone, laptop, and camera battery all plugged directly to the power outlet with no issues. But if you've got older devices or some specialized tools you may wanna check the voltage requirements just in case