In this paper we discuss the introduction of collaborative writing (CW) tools in a course designed with learning activities based on problem-based learning (PBL), authentic case methodology, and teamwork. We argue that CW is a vital, but poorly understood, part of teamwork, and a black-box activity. Our ambition is to open the black box of CW and discuss how CW concepts can enrich teamwork activities. We build on our students’ reflections on challenges linked to CW in a teamwork setting. In total the data consisted of 77 individual reflection papers, which were analyzed using constructs from prior literature on CW. Our results show that our students actively used CW tools and strategies and that CW had a large impact—and, in fact, enhanced teamwork management. The CW tools also helped in creating sustainable teamwork in the sense that they enhanced the three criterions of team performance: productivity, cohesion, and learning.