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).