It works fine but with any trip abroad, you need to be attuned to the cost of data usage (not just for map usage but for all other things you use your phone for) with your carrier. Costs vary from carrier to carrier, some have reasonable charges for international use and others don't. If you have an unlocked and global phone, it can be cheaper for some to buy a local SIM card - often $15 or so for a good chunk of data, and then put your US SIM card back in when you get home. But if you do that, you won't get phone calls to your US number. That can be a benefit because of the cost. Some carriers have special deals for Canada and Mexico visits, another thing to check into.

On Android phones, Google Maps has a WIFI ONLY choice under Settings. If you turn this on, then download (over Wifi) map data for the area you will be in, you can then use the Nav feature of Google Maps using only the GPS signal and the onboard downloaded map data. This approach uses No cell data at all. It's a cool feature and you can download the map data before you leave home. Do use a Wifi connection for the download, it can be hundreds of megs of data.

PS - Wifi only also works in the US. I have a car with Android Auto compatibility (which makes the car's screen act as a slave for Google Map navigation). It works great but sucks up data, so I use the Wifi-only feature often. The downside is that you need to be using the real-time signal (not the Wifi setting) to get traffic information and rerouting. For me, I need that sometimes but not other times, so I toggle between the two to maximize usage of the feature without running up a large data cost.

WhatsApp works well if you want texting.

What's App works fine so long as the people you communicate with have What's App accounts. Skype can be used the same way.

You can't send or receive SMS messages (the normal text messages) using What's App, though you can with Skype (for a small charge).

I live in and purchased my car in California. The navigation system includes Canada. But not Mexico.

We have an unlocked phone and have a UK sim card in it (it's where we travel most). We buy "minutes" for the phone each month that has 1GB of data to keep the number active (so relatives can call us easily). We buy an unlimited data package while we're in the UK and tether our US phones to it. Our US phones (with a special AT&T overseas package that we buy before we go) allows x-number of free text messages that we'e never exceeded, and a certain amount of data - which is why we tether our phones to the UK unlimited phone.

WiFi works just fine in the UK and France, as long as it's available.

Let me know, how google works for you. I will be in Ontario this year too.

Moni