There are more Christians in South Korea (the Republic of Korea) than in other asian countries such as China and Japan, so Christmas is celebrated more widely. (Christians make up about 25-30% of the population.) However, the other 70% of people in South Korea are Buddhist (about 25%) or don't have a religion.
Unlike Japan, Christmas is an official public holiday - so people have the day off work and school! But they go back on the 26th (Boxing Day). There's a longer official winter break in the New Year.
Churches are decorated with lights and many have a bright red neon cross on top (all the year!) so that goes very well with the Christmas lights! Most churches will have a service on Christmas day. Going to Church for Christmas is becoming more popular, even among non Christians.
#508429971 / gettyimages.com
Department stores put on big displays of decorations. There's also an amazing display of lights in the capital city, Seoul. The lights are all over the city centre including the bridges over the Han River.
Some people (especially Christians and westerns who live in South Korea) will have decorations at home including a Christmas tree.
Presents are exchanged and a popular present is money! Giving actually gifts has become more popular, but giving money is still very common.
Santa Claus can also be seen around Korea but he might be wearing red or blue! He's also known as 산타 클로스 (santa kullosu) or 산타 할아버지 (Santa Grandfather).
A popular Christmas food is a Christmas Cake, but it's often a sponge cake covered in cream brought from a local bakery! Or you might even have an ice cream cake from a shop like 'Baskin Robbins'!
Happy/Merry Christmas in Korean is 'Meri krismas' (메리 크리스마스) or 'Jeulgaeun krismas doeseyo' (즐거운 크리스마스 되세요). Christians can say 'Sungtan chukhahaeyo' (성탄 축하해요) to celebrate the birth of Jesus. Happy/Merry Christmas in lots more languages.
If you live in North Korea (Democratic People's Republic of Korea) Christmas will be very different. Being a Christian is 'officially' allowed but you can go to prison, or even be killed for being a Christian or even having a Bible. Christians in North Korea have to meet in secret and any celebrations of Christmas will also be held in secret.
Thank you to Heidi Wenger for her help in giving me information on Christmas in South Korea!