You can also pull up basic maps for locations offline.
This means that even if you enter an area with poor cellular service, navigation will still go relatively smoothly as long as you have 'Location Services' enabled. While it doesn't offer an obvious option for offline navigation outright, Apple Maps nonetheless has this feature built in, as it caches your current destination and saves it until you end your route. Apple Maps also lets you use its service offline on your iPhone, though the feature is not as straightforward as it is on its competitors.
Whether due to spotty cellular reception or just data that you want to save, popular navigation apps like Google Maps and Waze offer an offline feature that lets you navigate from one location to another in the absence of internet service.