The present study aimed at examining the combined effects of pre-task and online planning time on complexity, accuracy, and fluency in narrative-based texts produced by Iranian intermediate EFL learners. Overall, the implemented studies in this regard point to the facilitative impacts for both pre-task and careful online planning on complexity, accuracy, and fluency with some recorded trade-off effects. Using a between-groups design, sixty homogeneous participants were randomly assigned to four performance conditions: no planning (NP), careful online planning (OLP), pre-task planning (PTP), and both pre-task and careful online planning (POLP). The findings revealed that pre-task and careful online planning don’t have any significant effects on the level of complexity. The results also suggested that whereas the provision of abundant online planning time increases the accuracy level, the opportunity to plan prior to performance leads them to generate more fluent written discourse. In addition, compared with the NP condition, pre-task in tandem with careful online planning time enable the participants to produce more accurate, and fluent written discourse that lend support to the Dual-Mode system and Limited Attentional Capacity Model. The findings are of pedagogical significance in that they speak of the efficacy of planning as an important metacognitive learning strategy capable of helping teachers achieve the desirable pedagogical objective of enhanced complexity, accuracy, and fluency of learners’ task-based production. Theoretically, the results underscore the effectiveness of planning time in helping language learners overcome the limitation of their attentional capacity and direct them towards aspects of form and meaning.