My provider had an international plan so I had data almost everywhere I went (ofc with a daily price), but you can buy a cheap sim card at the ICN airport. For navigation, KakaoMap and NaverMap will be your best friends. Google maps is good if you need to use subways or buses but for whatever reason the Google Maps satellite doesn't show directions if you want to travel by car or if you want to walk. I would just use Google maps to find stores or places I wanted to go, and then copy the Korean address that showed up on Google maps into the Korean navigation apps. NaverMap is easier with using English, but imo it's less reliable. I liked KakaoMap better, it tells you how much a taxi ride or a bus/subway ride costs depending on your destination. But most of the app is in Korean and you can't search any place up even when using the romanized version of the Korean words. So I'd suggest saving/bookmarking important places on the app before you get to Korea so you can be more prepared.I'm going to South Korea for the first time for an upcoming procedure. Feeling a bit nervous for the procedure but I'm even more nervous on how to get around, especially figuring out how to get from Incheon airport to Gangnam. Does anyone have any pointers or guides on how to navigate this?
For going from ICN to Gangnam, you can use the Uber app to call a taxi (I didn't notice any price difference between Ubering vs calling a taxi). I just directly went to the taxi stand at the airport. There will be a bunch of taxis there along the sidewalk.