This paper deals with a phonotactic constraint imposed on surface coda-onset clusters in Korean. In mono-morphemic contexts, these clusters appear intervocalically but they are ruled out in initial or final position. In order to account for this asymmetrical distribution, this paper adopts the notion of syntagmatic licensing. In intervocalic position, a coda consonant requires not only a licensing from a preceding vowel but also a licensing from a following onset consonant which, in turn, needs another licensing from a following vowel. When either of these two conditions is not met, coda-onset clusters in question are not allowed to occur in Korean. To empirically support the asymmetrical distribution of coda-onset clusters in Korean, this paper takes consideration into loanword adaptation in which we observe initial and final epenthesis of [i].