Digital visual mapping to date has recently been implemented in an English Foreign Language (EFL) classroom. However, there is a growing need to implement this digital mapping tool within a strategic approach for more effective and self-regulated learning. This paper aimed to investigate the effects of Computer-Aided Argument Mapping (CAAM) within the metacognitive approach on Thai EFL learners' argumentative writing performance across the development of writing content and writing coherence and their self-regulation of learning. A mixed-method type of research was employed involving a one-group of pre- and post-test design. A total of 21 Second Year college students was purposively selected as samples. A Self-Regulation of Learning Scale (SRS) was also used to track the development of their self-regulation. Results reveal that students' argumentative writing performance made noteworthy gains as manifested by a significant difference between their pre- and post- test results. Furthermore, five of six SRL components reveal a significant relationship with students' argumentative writing performance indicative that they have become more self-regulated in their learning in terms of planning, self-monitoring, evaluation, effort, and self-efficacy. Qualitative findings reveal that the participants have positively welcomed the use of CAAM on their writing processes and self-regulation. Finally, the study findings provide thoughtful insights into utilizing digital mapping within the metacognitive approach to improve students' argumentative writing skills and self-regulated learning as well as revolutionize EFL learning classrooms in this digital period.