It’s different from the U.S. or anywhere else for that matter, since every community is different, but racism, colorism, and antiblackness are still very much present. White foreigners are lionized while SE Asians and Black people are looked down on. There’s a large population of marriage immigrants from Vietnam and elsewhere who endure high rates of abuse and violence from their husbands and in-laws, often in isolated rural settings. Workers from SE Asia, Africa, and the Middle East often suffer from bad working conditions and have no bargaining power under an immigration law that gives all the power to employers. A few hundred Yemeni refugees arrived in Jeju Island back when it had a more liberal entry policy, and the widespread pushback against accepting them has been heartbreaking and infuriating.
There’s xenophobia that can’t be neatly fitted into racial categories, for example against Chinese citizens of Korean heritage who are technically the same race and ethnicity as Koreans. There’s a class element going on here, too, as Korean Chinese are treated very differently from Korean Americans who are assumed to be richer and better educated. There are cultural clashes with and prejudices against Korean Americans as well, of course.
We have serious prejudices against Koreans against mixed heritage. The nationalist myth (and it is a totally fabricated myth) of Korean “purity of blood” has a toxic effect on the lives of people with a non-Korean parent. Mixed Koreans with a white parent are treated the least worst, although they too are subject to unwanted attention and fetishization that I imagine is uncomfortable for them. Koreans with a Black or SE Asian parent are treated considerably worse, subject to the racism faced by their non-Korean parent and lack of acceptance as Koreans. North Korea has the same prejudices, only more violently expressed under an authoritarian regime. I have read reports of North Korean authorities committing infanticide against babies born to NK women returned from China, the reason being that the babies were “Chinese seed.”
A huge number of Korean children of mixed heritage, generally those born to SE Asian women, are subject to racist bullying in school. The first generation of these children since the start of marriage immigration policy are now grown and we should be seeing them in society, but we just… don’t. They don’t seem to be going on to higher education or being hired for jobs. This is really disturbing, that we now have an entire contingent of Koreans who have been pushed out from mainstream Korean society by racism. This is not to say that other factors like class and the marginalization of rural areas are not issues, but racism is a huge factor as well.