The study aims to analyze speaking efficacy of Japanese Korean language students and identify implications for further speaking instruction. The responses of 103 Japanese Korean language learners were analyzed. Korean speaking efficacy of Japanese students is 2.31, which is low compared to the highest possible value of 6. An interview was conducted targeting 13 Japanese Korean language students and 9 Korean language teachers. The reasons for Korean Japanese language learners’ low levels of speaking efficacy are as follows: First, Japanese Korean language learners think that other people’s evaluation is important. Therefore, they are overly concerned with whether the listener is able to understand their speech. Second, since speaking is instantaneous, they experience difficulty when attempting to express themselves quickly. Third, their imagined standard of speaking proficiency is higher than other language learners. And they think their utterances should be perfect. Fourth, humility which influences the efficacy of Japanese students is considered virtuous in Japanese culture. Based on the results of the interview, the teaching implications Korean language instructors of Japanese students are as follows: First, preparing for the next class’s topic in advance is recommended. Second, pre-speaking task activities should be explained in detail. Third, teachers should develop small group activities in which students have the opportunities to speak with language learners of different nationalities in small groups. Fourth, teachers should create an atmosphere that accepts mistakes. Fifth, teachers should help Japanese Korean language learners develop rapport with teachers and classmates.