Mount Seorak is gorgeous. I definitely love its view in autumn but winter and spring will be just amazing too. Read my Mount Seorak 2D1N trip with a budget cost here and my Mount Seorak one day trip here. The above picture was taken on 8th of April 2015.
First and foremost, there are two options (with express bus) to go from Seoul to Sokcho; where Mount Seorak is located.
You can take express bus from Dong Seoul Terminal (Gangbyeon Station, Subway Line 2) and it will arrive at Sokcho Intercity Bus Terminal.
Dong Seoul Express Bus Terminal
Sokcho Intercity Bus Terminal
You can take express bus from Gangnam Terminal (Express Bus Terminal Station, Subway Line 3,7,9) and the bus will arrive at Sokcho Express Bus Terminal.
Seoul Express Bus Terminal
Sokcho Express Bus Terminal
It all depends on where do you stay at Sokcho and what is your next plan?
For me, if I want to go to Nami Island after visiting Seorak Mountain, I will take the first option because the bus to Chuncheon goes from Sokcho Intercity Bus Terminal.
If you plan to go back to Seoul immediately, either station from Seoul does not matter.
Express Bus Ticket Online Purchase
At the moment the English site is not equipped with online purchase however the Korean site is possible.
For DongSeoul (Gangbyeon Terminal) to Sokcho, buy the ticket online from the websites below:
English site: http://www.kobus.co.kr/web/eng/index.jsp
Korean site: http://www.kobus.co.kr/web/main/index.jsp
For Express bus terminal to Sokcho, buy the ticket online from the website below:
Korean site: http://www.exterminal.co.kr/
The ticket price differs between date of purchase, departure time and terminals. Basically it is between 17,000~20,000won per one way journey.
If you don’t know Korean, just ask the reception of your boarding in Seoul to do the ticket purchase online a few days before you go to Mount Seorak. They will gladly help you.