Previous research suggests that the affordances (van Lier, 2000) of asynchronous computer-mediated communication (ACMC) environments help reduce foreign language anxiety (FLA). However, FLA is rarely the focus of these studies and research has not adequately addressed the relationship between FLA and the affordances that students use. This study explored sources of FLA in an oral ACMC environment, and how the affordances perceived by students in this environment correlated with FLA. One class of Korean EFL university students (n = 15) completed voiceboard tasks for eight weeks. Affordance data were collected with a questionnaire, and FLA was measured qualitatively and by employing an adapted version of the foreign language classroom anxiety scale (Horwitz, Horwitz, & Cope, 1986). The results suggest that students experience FLA in particular ways using the voice board, and that some sources of anxiety are similar to those reported in face-to-face contexts and others are unique to ACMC contexts. Additionally, this study found a moderate correlation between the total use of affordances and FLA, with some affordances being associated with reduced anxiety and some associated with higher anxiety. The study discusses these findings and identifies avenues for future research examining the interplay between the ACMC environment and FLA.