Although Waze comes into its own when you're connected to the internet, I discovered you don't actually need an active connection in order to follow a route. It means you won't lose your way in areas with poor cell service or use up your monthly data.
It won't, of course, be able to give you live traffic updates or alert you to hazards, though. For that, you'll need to go online. You won't be able to contribute real-time reports or benefit from them either. Again, those are online features.
To that end, you're not going to get anywhere near the full Waze experience but that's to be expected. The important thing is that you won't get lost — even if you accidentally close the app, because the saved route data remains intact for a while.
Here's how you can turn on Waze's offline maps featu