Ah, yes. The dreaded "I'm from _____! How can I be an idol in South Korea?!" question. 

You know, unlike what everyone else says, living in a different country and wanting to become an idol in Korea isn't really a bad thing, but I personally think it's a bad idea. Why? Well, you're automatically at a disadvantage because you're not Korean. Of course, let's say you ARE Korean, but let's be real here. Chances are, you will obviously have an accent when speaking Korean and that will make it obvious to other auditionees, judges, and/or trainees that you're an "outsider."

But, once again, let's be real here. I'm sure the majority of you guys reading this aren't Korean and you probably live in a different country like the states, Canada, or even Europe. How do you even come close to being part of the entertainment world when your ethnicity/nationality/location is a big problem? Well, you need to put your negative feelings aside, children! Even though you're not privelged like Korean citizens who can just walk in during open auditions, there are still actually other ways to audition for a company. For example:

1. If you live in country that holds global auditions, you can go to these. Of course, I know many places (like Canada's Toronto) are often overlooked by Korean companies, but don't worry, your city's time will come soon!

Experience time! Although global auditions are a good way to go, be prepared to be surrounded by many idol hopefuls! I've had the chance to audition in SM and JYP's global auditions and you do not know how many people I had to swim my way around. I arrived about 1 ^1/2 - 2 hours after the auditions opened, and I was in the early 200's, meaning 200 people came ahead of me. Like any audition, you're going to be around people who are busy practicing for whatever section they're auditioning for. Every where I looked, I saw and heard people singing, rapping, dancing, and even perfecting their modeling walk and poses! 

2. Sending in your audition tapes via email or mail. It's exactly what it sounds like. You film yourself doing yo thang and you send that in with your application that you can find on the company's website.

Experience time! This was actually the way I got accepted by my company. I sent in a tape of me rapping and singing and after a week or two, I was given a call that the company was interested in me and offered to either fly me to Korea to have my audition in person, or they could send a few representative to my city so I could audition here. Since I couldn't leave the country at the time (exam week, yipee), I took the offer on auditioning in my home town. Long story short, I was contacted a few weeks later with the final result. 

3. Flying to Korea and attending an open audition. Okay, so this option is for them ballers, 'na what i'm sayin? Aha, okay, besides them, maybe also for the people who are already going to Korea on a vacation and would rather take advantage of the trip.

Experience time! I've never done this, so I can't help you, brah.

Time for the "Wow, that was rude and somehow it's making me extremely uncomfortable."
Although I say it's fine for a non-Korean to audition, some of you have to realize that when I say you're at a bigger disadvantage, I mean chances are, you may or may not be given a second look at. What I'm trying to say is that if you don't have that East Asian look, most judges will give you that "Why are you even here?" look. Hell, they might not even bother looking at you. Because, honestly, how many idols have you seen that are not Korean, but don't have that East Asian look? The majority of idols that aren't Korean are either from China or Japan. 
What I'm trying to say is that (wow, I've been saying this a lot) if you don't have that certain "look," you're going to be at a HUGE disadvantage no matter how talented you may be. BUT THAT DOES NOT MEAN YOU WILL NOT BE GIVEN A CHANCE. If you are confident in your ability, you should still try. South Korea is slowly changing, and who knows, maybe they'll start accepted other looks? c:

Remember: confidence is extremely attractive and if you're completely confident in yourself, the judges and spectators will take notice.

edit: for those that aren't sure what "east asian" looks like, I'm speaking in a very vague and stereotypical way. East Asian means those from places like Japan, China, and Korea. The look most companies are looking for includes: pale skin, big eyes, double eyelids, high nose, etc. Again, this is a VERY vague and stereotypical view on what East Asian females and males are "supposed" to look like. Not everyone will look this way, but this is the "look" most companies are looking for.
 

TL;DR: yo man, don't be discouraged. there are other ways to audition for companies, but if you're not a native korean or you don't have that east asian look, you're going to be put at an automatic disadvantage.

note: if this post happens to offend you (especially the second half), I apologize. My original intention was not to offend anyone about any matter. Thank you.