Traveling to Korea, I don't want my parents to know.

Isn't it just setting up mobile roaming and opening up international services? A phone call every day is like being around.

However, I suggest you don't hide anything from your parents. In case of any special circumstances, it will be bad for you. You should tell your family who you went out with and where you went. I think parents will be reasonable, even if they don't particularly agree, they won't absolutely object. Let's communicate more.