Teachers should expect to have ten days vacation included in a standard contract agreement. However some contracts vary depending on the policies of the school. Most employers grant five days in the summer and five days in the winter for vacation.
Mostly hagwons offer 10paid vacation. Usually hagwons that have kindergarten and elementary school students provides consecutively 5 days in summer and 5 days in winter , however hagwons that have elementary and middle schools students will close 2 or 3 days in summer and winter respectively and teachers also will take vacation at that time and remaining vacation days will be used whenever you want but you have to give notice to your supervior what date you will use it.
National holidays are also days where teachers are not expected to work and schools are usually closed.
Korean National Holidays in 2008