If you are a foreigner, this will do a great job getting you lost – NAVER Map, Navigation Review

If you're a foreigner living in Korea, you are probably using Naver because Kakao does not have an English version, and Waze and Google Maps don't work well here due to Korea's data restrictions. The problem is that Naver is a terrible app. It's AI is awful. The worst feature (by far) is that it constantly tries to re-route you in directions that make absolutely no sense. It simply refuses to stick with an initial route. It will give you a different route every single time. I've given up on this app. You're better off just using trial and error.
Review by straight furrow on NAVER Map, Navigation.