Research suggests that pre-task planning time provides learners with opportunities to formulate, organize, and mentally store content, thereby freeing up attentional resources during tasks (Skehan, Xiaoyue, Qian, & Wang, 2012). However, relatively few studies to date have investigated pre-task planning in a synchronous computer-mediated communication setting (e.g., Lai, Fei, & Roots, 2008; Hsu, 2012, 2015). In addition to a scarcity of computer-assisted language learning research, relatively little is known about what learners do when they plan or how they use their plans during tasks. The goals of the current study were twofold: (a) to examine the relationship between pre-task planning and learners' production and (b) to explore the affordances offered by computer-mediated contexts to further investigate how and what learners may (or may not) be planning during pre-task and within-task planning time. Results suggest that three minutes of planning time resulted in increases in lexical complexity (but not phrasal or syntactic), although no significant findings were identified for accuracy or fluency. In addition, findings indicate that technology offers researchers a number of unique methodological affordances, such as the ability to see what learners produce, regardless of whether they transmit this information to their interlocutor, thereby providing evidence of L2 knowledge that would otherwise be unobservable.