I am traveling to Khao Lak and Phuket in February. I am considering doing 1 to 2 hours of work per day which would require a good data connection (setting up my phone as a wifi hotspot for online computer work) and a good voice connection (either by regular mobile phone voice plan using a Thai sim card, or preferably by VOIP softphone using a good cellular data connection). And hotel wifi is never up to the task.

If I get a Thai sim card with voice and data, will the data connection be fast and reliable enough to do VOIP calls from my laptop? Will there be much lag / delay on VOIP calls halfway around the world? I understand that Thai sim card plans with voice and data are cheap, but I imagine long distance rates for an hour or so a day on the phone to Canada would be prohibitive. At home my work calls are over VOIP and I hope to use the same setup in Thailand. So info on the speed and reliability of mobile data connections in Khao Lak and Phuket would be most appreciated