Japanese allows for almost no consonants in syllable codas. In loanwords, illegal codas are transformed into onsets by means of vowel epenthesis. The default epenthetic vowel in loanwords is [ɯ], and previous work has shown that this [ɯ]-epenthesis reflects Japanese listeners’ perception of illegal coda consonants. Here, we focus on one of the non-default cases: following coda [ç] and [x] the epenthetic vowel is a copy of the preceding vowel. Using an identification and a discrimination task, we provide evidence for the perceptual origin of this copy vowel phenomenon: After [ç] and [x], Japanese listeners perceive more often an epenthetic copy vowel than the default vowel [ɯ], whereas after [k] it is the reverse.