It’s been recently uncovered by the folks at Android Police that the new version of Google Maps for Android is now letting users set Google Maps to only work in WiFi mode. When a user’s Google Maps is set to this mode, you won’t have to use your cellular data while using Google Maps. This is, assuming that you’ve pre-downloaded the maps before you left your WiFi connection, though.
When you put your Maps app on to the WiFi only mode setting, it’ll be possible to access it by opening the Settings screen and looking for a new toggle on the second line with the title, “Wi-F only.”
If it’s there, you’re set to go offline. This line used to be titled “offline areas,” and it still provides a link to the same screen if you tap the description, but it has been augmented with the new title and the switch. Just be aware that tapping the title or switch will effectively cut maps off from cellular data, and tapping anywhere on the description will open the configuration screen for offline areas.
The image below shows the setting: