A few years ago, only a few GPS navigation apps for smartphones (and GPS-capable tablets)\u00a0let you download and save maps, instead of downloading as you needed them. Today, dozen of these apps exist.\nThat's great news, because downloadable maps work without an Internet connection, and they're ideal for driving through areas with spotty or non-existent cellular coverage. Downloadable maps can also significantly reduce data use and roaming charges when you travel internationally.\nThese three popular mobile GPS apps all offer offline maps.\nSygic and offline maps\n\nAverage Google Play rating for Android app: 4.3 stars\nAverage Apple App Store rating for iOS app (all versions): 4 stars\nAverage Windows Phone Store rating: 3.6 stars\n\nSygic claims to be "the world's most installed offline navigation app," and it has downloadable 3D maps that span the globe. The app is free, and you can download offline maps for more than 100 countries at no charge. Some features, however, are restricted to Lifetime Premium subscribers, including turn-by-turn navigation. You also need a Lifetime Premium license to receive map updates, and the costs vary. For example, the "World" license, which maps nearly the entire globe, is currently on sale for $38, down from the normal price of $125.\nMaps.me and offline maps\n\nAverage Google Play rating for Android app: 4.4 stars\nAverage Apple App Store rating for iOS app (all versions): 4.5 stars\n\nMaps.me is one of several apps that receive map data from the open-source OpenStreetMap (OSM), a kind of Wikipedia for maps. The app is free, as are the maps you download, but it lacks some basic features of other GPS apps, such as voice-guided navigation and real-time traffic. It also works on Apple Watch.\nNavmii (formerly NavFree) and offline maps\n\nAverage Google Play rating for Android app: 4 stars\nAverage Apple App Store rating for iOS app (all versions): 4.5 stars, USA app\nAverage BlackBerry World store rating: 4 stars\nAverage Windows Phone Store rating: 3 stars\n\nNavmii, which claims to be the first free iOS navigation app, also gets its data from the OSM. The app offers free, real-time traffic and road data (though you need an Internet connection to receive it in real time), along with voice-guided directions and other features. The apps are free but include ads, which you can get rid of for $2. Other paid upgrades add voices from celebrities, including Snoop Dogg and Homer Simpson.\nEach of these apps is worth a download, but if you still seek additional GPS navigation software with downloadable maps, consider CoPilot Premium, Here, OsmAnd, and Navigon. Google Maps also lets you save selected map areas to your mobile device.