The present study was an attempt to investigate the differential effect/s of three different planning time scenarios (i.e. 0 min, 10 min, & 20 min), as well as three task conditions of (1) topic given, (2) topic and ideas given, and (3) topic, ideas and macrostructure given on EFL learners L2 writing complexity, accuracy and fluency (CAF). One-hundred-eight male and female participants were randomly assigned to three time-conditions, each with 36 members. Each time-condition group was itself divided into three smaller groups of 12, each with a particular task condition. The results of the comparison of the groups who were engaged in the argumentative writing task revealed that planning time significantly influenced the complexity of the essays, and the writers in the 20-minute planning time group produced more complex texts compared with those in the zero-minute planning time group. However, no significant effect of task conditions, as well as no interaction between planning time and task conditions were found. Moreover, task conditions affected the general accuracy of the writers’ performance in all tasks. The pairwise comparisons showed a marginally better accuracy of texts in the condition of topic, ideas, and macrostructure given as opposed to the topic given condition. The findings of this study provide beneficial implications for language teachers and learners in developing their writing quality particularly with regard to the CAF triad, and stress the significance of planning time before conducting a written output task in the complexity of the output.