Navmii is a free offline map/gps alternative which you can use on your Anroid device, without worrying about mobile data. It's ideal for taking on the road, when your tariff may not allow you to use data abroad.

Navmi is easy and simple to use once you have downloaded your chosen free map on your iPhone (you can download additional country packs for a fee). Although it is ad-based, you can remove these for a small $2 fee. You can also download add-ons such as speed and red light camera information.

Once set up, all you need to do is enter the address or postcode of your destination. It will plot the best route at that time, then you can use the map offline, without data, to navigate the preset route to this destination. 

If you want to continue to use data, or you have access to wifi, then you can search for names of businesses, additional locations and also get additional features such as the location of speed cameras, traffic and accidents. The maps come with points of interests, but you have to activate them from the default setting.  

The only downside is the mapping simplicity. Roads don’t necessarily show turns as you would find when driving for real and the voice over does not say street names. However, this could be compensated for by downloading a celebrity voices such as Stephen Fry, to guide you to your destination.