Busan

Busan is a hidden gem for summer runaways from the SE Asia heat. It's a great city for cafe-hopping. There are nice cafes almost everywhere in the city. You normally don't have to worry about the internet as almost every cafe I've visited has strong WIFI. The city is very walkable. You can enjoy mountains beaches and many city scenes. There's even a surf town in the city. Public transportation is very advanced and convenient so you won't need a motorbike or a car. So many gyms around the city so its easy to keep your exercise routine. The only missing piece is some good community vibe coworking space as there are a few coworking places in the city but they are intended for startups rather than nomads. But a quick solution is to just work in cafés. In general, the living cost is about twice of Thai and Vietnamese cities. Probably a bit more than Canggu Bali; but you get the extra values of a modern city with all the things to do and convenience.

Gimhae is a nice area to stay if you enjoy nature, art galleries, shops, and a smaller city feel near the airport. You will have access to Busan as well. The light rail is a handy automated above ground rail to use. The line goes into Gimhae, to the Gimhae International Airport, and slightly into Busan before having to shift to another metro or transportation line. Gimhae also has a Costco and major supermarkets. The street art is also quirky.

Great place if you like Korean cuisine and fresh fish in general. Haedong Yonggungsa seaside temple is the absolute highlight. Locals are helpful, too bad 8/10 won't speak english. Young people included!
Remember: Uber, Grab, Google Maps won't work in Korea, in favour of Kakao app which is pure garbage and all in Korean.
And by the way pornography is illegal.

Korea's second biggest city after Seoul. Busan is a nice place to go if you want to see another part of Korea that's still pretty comfortable. It's in the south of South Korea, on the ocean, and that makes it a great place to eat fish. In fact that's where all the fish in Seoul comes from, so you can eat it fresh in Busan! In many ways Busan feels like Seoul but 10 or 20 years ago. It's a bit more grimy and broken down and less futuristic than Seoul, but still very nice. I'd suggest staying in Seomyeon, which is kinda like Seoul's Hongdae. It's a student area with some hipster vibes to it. But take hipster vibes with a grain of salt, this is Busan after all. People are very friendly, even more friendly than Seoul. Where in Seoul as a foreigner they don't really care anymore, in Busan you're still hailed as a curiosity which can be fun! If you want to see the beach, take a taxi to Haeundae Beach. It's especially nice in the evening if you'd like to party. Korean beach culture is a bit different than in the West, so you'll probably see less swimming and sunbathing that you're used to. More like people walking on the beach boulevard. Also nice is to see the Jagalchi fish market, pick some fish you like in the big building and you can ask them to prepare it for you upstairs and cook it. Fish as fresh as you can get in Korea.