OrganicMaps works well. I travel to Andorra frequently, and because they are not in the EU it’s not free to roam there. Organic maps allows you download the entire country at a time and navigation and searching all work without data. I use it quite a bit in the mountains even in countries I have data in. Since it’s just OSM data it has a decent selection of hiking trails and whatnot, too.
I was pleasantly surprised how polished it is (on iOS at least). I had only ever tried OSM AND before it and this is leagues ahead in terms of usability. It’s more or less as good as Google Maps or Apple Maps, short of real time traffic updates. It’s navigation routing is not quite as advanced either, but it does the trick in a pinch (I don’t use it much in the car but more for searching and hiking trails)
I was pleasantly surprised how polished it is (on iOS at least). I had only ever tried OSM AND before it and this is leagues ahead in terms of usability. It’s more or less as good as Google Maps or Apple Maps, short of real time traffic updates. It’s navigation routing is not quite as advanced either, but it does the trick in a pinch (I don’t use it much in the car but more for searching and hiking trails)