Within the burgeoning literature on online formative assessment mediated by particular ICT tools in writing courses, the scrutiny focusing on the enactment of assessment for learning (AfL) in the similar context has been inadequately addressed. This current study, therefore, is in an attempt to fill this empirical void by exploring how EFL teachers implement the AfL on their writing courses. This narrative case study recruited three Indonesian EFL undergraduate teachers. They were invited in a series of interviews mediated by WhatsApp video call and voice notes. Nested in the AfL framework, proposed by Lee (2007b), the participants' stories were analyzed thematically. The findings indicate that, in line with AfL framework, the teachers were able to enhance planning and pre-assessment instruction, share learning goals with students, use feedback forms in feedback delivery, apply self- and peer-assessment, and relate assessment with the pedagogical instruction. Albeit the perceived positive practices, the teachers also experienced some hurdles to engage students in the multiple drafting and sustained reflective process. Some implications and future research direction are also discussed accordingly.