You can save a offline map to your device and uses it when you’re offline.
To use Google Maps offline on both iOS and Android, visit App Store on your iOS device, or the Play Store on your Android device and check for any available updates for Google Maps.
Launch Google Maps on your device and search for the area you’d like to save for offline use. Now click on the three dot icon in the top right corner of your screen to save offline map of respective area. There are some limitation on Google Maps, you can save area less than 50km x 50km and not able to use navigation on offline mode.
To overcome Google Maps limitation, You can also use Here Maps by Nokia, Download and install it on your Windows Phone, iOS and Android device. After installing to your respective device, navigate to download Maps and choose city or country name to start download.
If you have some other methods for offline maps, tell us by commenting below.