Google Maps for Android has had some sort of offline support for years now, but it’s definitely not good enough for most use cases, in the current iteration at least. At its I/O conference Google has announced that it’s working on bringing better offline support to Maps sometime before the end of this year.
So in the future you’ll be able to start navigating to places while offline. Currently navigation works offline, but you need to be online when you start it. Additionally, Google Maps will allow offline searches for places and points of interest (with autocomplete no less), something which you can’t do right now.
Reviews and important info such as opening hours show up too. You will still need to initially save the desired maps to your phone, of course. Turn-by-turn voice directions will be available offline too.
Unfortunately the short presentation about this topic was very light on details, so we don’t yet know how much space the saved offline maps will occupy on your device. That may be an issue, as you’d imagine. It’s also unclear whether these new features will become available globally from the get-go, or if we’ll see a more limited rollout first.