I see lots of tourists in Seoul.
Tourists seem to outnumber Koreans in certain areas near the Dongdaemun (West Gate) shopping area.
I visited Phenom Penh, Bangkok, Tokyo, Los Angeles, Amsterdam, London and many more cities and saw other Koreans, Chinese, British, and tourists of other nationalities everywhere.
If China forgives South Korea for allowing US's THAAD anti-missile system to be installed in Korea and removes its unofficial boycott of Chinese tourists to South Korea, I should see even more Chinese while walking through my neighborhood, which is next to Dongdaemun.
Tourism is becoming really big in Korea and all over the world, it seems. A few decades ago, there were very few tourists.
Lots of expatriates living in Korea. Also, the number of families of mixed races has risen sharply over the past decade. Korean-Vietnamese, Korean-Cambodian, Korean-American and so on.