We are headed to Italy, Slovenia, and Croatia soon. We would like to bring our phones (from Canada) . Looking for recommendations for SIM and phone plans that can be used in these three countries. Thank you.
TMobile ............
All 3 countries listed are in the EU and subject to roam like at home regulations. I would pick up a local SIM card at my first destination. For Italy TIM gets many good reviews from forum members. I have used vodafone Italy with no issues. I did not use their roaming service.
A side note. When I read you location I was thinking London UK not Ontario. On the off chance that you are in the UK, EE still allows free EU roaming on their pay as you go plans.
Oh and if you only need data and have a dual SIM phone there are e SIMs like Airalo.
Unfortunately, T-Mobile isn't available in Canada.
On my trip to Slovenia, I got a local sim card, which worked fine but all the notifications were in Slovenian and to add to my card, they spoke in Slovenian. So, last trip (to Italy) I purchased a UK sim card (on Amazon ahead of time) so that I could read any notifications, etc. That worked better for me.
The Orange Holiday SIM (French) ought to work. Good for two weeks after activation. After that you may be able to top off online - or buy a SIM in Slovenia or Croatia to continue.
Or buy an Italian SIM, TIM or Vodafone, upon arrival in Italy (if you start there) and try to use that for the rest of the trip.
https://www.amazon.ca/Orange-Europe-Prepaid-SIM-Card/dp/B0B7WZT4ZF/