Koreans celebrate their birthdays with many unique customs. Here are some common examples:

1. Birthday cake: Birthday cake is a necessary thing to celebrate birthdays, usually a strawberry cake decorated with fruit and icing. In Korea, birthday cakes are usually given to the birthday girl by family or friends.

2. Birthday gifts: In Korea, giving birthday gifts is also a common way to celebrate. Usually send some practical things, such as cosmetics, clothes, shoes and so on.

3. Birthday Diet: In Korea, people will eat some special foods on their birthdays, such as birthday noodles and birthday rice balls. These foods are usually prepared by family or friends.

4. Birthday song: In Korea, birthday songs are sung on birthdays. This song is called "Happy Birthday". When singing, the birthday girl usually makes a wish and then blows out the candles.

5. Birthday party: In Korea, a birthday party will be held and family and friends will be invited to celebrate. It is usually held at home or in restaurants, and some people go to bars or nightclubs to celebrate.

The above are some common customs for Koreans to celebrate their birthdays, which all reflect the importance and enthusiasm of Koreans to celebrate their birthdays.