If you need to enter a contact number in Korea when applying for K-ETA, it is best to use the phone number of the place where you plan to stay or a place in Korea where you can be contacted.
Even if you do not know anyone in Korea, you may use a contact number that can be confirmed through your hotel, guesthouse, or accommodation.
If your accommodation has not been decided yet, it is safer to check your place of stay and available contact information first rather than entering a random phone number.
Entering incorrect contact information may cause issues during application checks or entry procedures, so please prepare accurate stay and contact information in Korea before applying for K-ETA.