The current study investigates and compares communication apprehension (CA) of the first-year MA students majoring in English in an international program in Bangkok of the academic year 2017. The research questions are: a) Is there any difference between CA in L1 (Thai) and CA in L2 (English) among the students in the study, b) Is there any difference in CA in L1 among the students in terms of their ages, and c) Is there any difference in CA in L2 among the students in terms of their ages. Quantitative approach is employed by making use of the Personal Report Communication Apprehension (PRCA-24). T-test is used to analyze the data. The participants are 32 students divided into 2 groups according to their ages. The results indicate that the students’ CA in L1 is lower than their CA in L2 across contexts. Students who are 30 years old or older are found to be with higher CA in L1 in meetings and public speaking contexts. However, for CA in L2, there is no difference among the students regarding their age difference. Benefits from this research for the students may occur when their instructors get the insight into their students’ communication traits when using L1 and L2 and they may select appropriate methods when teaching in the classroom and choose effective ways of communication when giving advice for writing a thesis or an independent study to the students of this MA program.