I'll be visiting Canada for 3 days and then US for 5 days coming from UAE during Nov.
I got some deals in Amazon:
T-Mobile Prepaid SIM Card Unlimited Talk, Text, and Data in USA with 5GB Data in Canada and Mexico for 10 days
T-Mobile Prepaid SIM Card Unlimited Talk, Text, and Data in USA with 5GB Data in Canada and Mexico for 30 days
When I should activate the sim online and physically
Any advice for my trip
Thank you so much
In general, you must first activate a T-Mobile SIM in the USA, on T-Mobile's network, for it to work.
There are prepaid plans that work in both the USA and Canada. Any of the Simply Prepaid plans work in Canada with the $5 bolt-on Canada option.
The only issue is that it must be first activated in the USA before any international (e.g. Canada) usage.
Manage your T-Mobile account