For third level domains, it is possible to register the letters a to z, the numbers 0 to 9 and the hyphen “-“.

For second level domains it is possible to register Hangeul characters, the numbers 0 to 9 and the hyphen “-“ with the exception of a combination of numbers and hyphens only.

For Hankuk domains it is possible to register letters of the Hangul, the letters a to z, the numbers 0 to 9 and the hyphen “-“.

However, it is not possible to register domains that begin or end with a hyphen “-“ or have two consecutive hyphens in the 3rd and 4th positions in both third, second and Hankuk domains.