Do Korean tourists need to cancel their visas after returning home?

There is no need to cancel the Korean tourist visa after returning home. A tourist visa is a valid visa and will be invalid once it is used.

Supplement:

Visa refers to the procedure of endorsement and seal of passports or other travel documents held by domestic or foreign citizens by the sovereign organs of a country to show that they are allowed to enter, exit or transit. It can also be said that it is an endorsement certificate issued to them. Generally speaking, a visa is a document issued by a country's entry-exit administration (such as immigration bureau or its embassy or consulate abroad) to approve the entry of foreign citizens. In addition to the validity period and stay period, the visa also stipulates the number of valid times. Generally, it is divided into one valid visa, two valid visas and multiple valid visas. The number of times a visa is valid means that once it is used within the validity period, it will be invalid. Two valid visas, that is, you can use them twice within the validity period of the visa. Multiple valid visas, that is, within the validity period of the visa, the holder can enter and leave its territory multiple times. For example, some tourist visas for Australia and India allow multiple entry and exit within three or six months. In some countries, work visas are also applicable to multiple entry. Of course, what kind of visa to issue, how long it is valid and how many times it is valid are decided by the visa authority according to the specific situation of the entry applicant.