Although things are changing slowly, the majority of korean women tend not to engage in one-night stands. However, there are some areas in Seoul where ladies opened to such an activity like hanging out.
Itaewon. Some Korean women adept of one-night stands like hanging out in the bars and dancing clubs in Itaewon where many foreigners spend their time (such as the bar "Hollywoods" for instance). It's generally not difficult for a caucasian guy irrespective of country of origin to find a partner there, especially if he has good looks and is not too picky. The korean girls who go there range from being ugly to average, often a bit overweight, often from a lower-class background, and tend to engage in one night stands rather frequently. What the ladies are expecting: to be treated like a princess for one night. Advice to the gents: use a mobeum taxi, get the nicest hotel you can afford, and compliment the lady restlessly all night on how good she looks. This being said, proper protection on all extremities is strongly recommended.
Hongdae and Daehangno. Hongdae is located in Mapo-gu nearby the Hongik University subway stop on line #2 while Daehangno is located in Jongno-gu nearby the Hyewha subway stop on line #4. In those districts during the weekend, there will be lots of young university students filling up the dancing clubs and the bars. While most who hang out there will not be opened to a one night love affair, there are some who will be. They are a small minority however, and good eyes are needed to distinguish them from the rest. Hint: since it is considered bad manner in korea for ladies to smoke in public, those who do smoke tend to be somewhat rebellious, and they can be rebellious in more ways than one. The Hongdae and Daehangno girls do not necessarily speak english and are considerably more picky than the Itaewon girls - but, they are also considerably prettier and are less likely to be one-night-stand addicts.
Night Clubs. Not to be confused with the dancing clubs, the so-called korean night clubs do not involve dancing and loud music. Rather, they are more-or-less quiet bars
in which the gents and the ladies are seated at different tables and exchange messages through a nightclub employee. In case of a good match, the gent can join the lady at her table. After some conversation, the pair might decide to go to a motel located conveniently one floor above or below. Night clubs are very popular with adjumas (housewives) in their 30s/40s/50s looking for a one-night stand with no strings attached. Foreigners are advised to go there with one (or more) korean friends or they might not be allowed in.
Myeongdong or other famous touristic spots. While most Japanese women are very reticent in doing one night stands in their home country, they seem to follow different rules when travelling abroad. They often approach korean or foreign males in the touristic areas of Seoul (such as Myeongdong, Namdaemun, Gyeongbokgung, etc) for the purpose of having an "adventure". Japanese women often travel in groups of 2 or 3 and it might be beneficial to bring a male friend along when going to these places - although threesomes have been known to happen. What japanese ladies like: british humour and oneliners, along with expressed interest for Japan and its culture.