The last few years have amplified the use of digital technology in the second language (L2) classroom due to the emergence of COVID-19. Students were forced to study online, and, as a result, changing the interaction among students became crucial. While most English Language Intensive Courses for Overseas Students (ELICOS) classrooms have since returned to face-to-face delivery, many providers are now considering the potential benefits of online learning and the strategies that make the platform and classroom interaction effective. One method of facilitating online interaction is collaborative writing (i.e., co-writing). Co-writing refers to two or more individuals producing work and contributing to a task together. While not a new phenomenon in face-to-face settings, this research project closely investigates the methods that students use to interact while completing co-writing tasks in an online environment and the impact these may have on L2 learning. The data, taken over five weeks, was collected from 15 adult English for Academic Purposes students in an online ELICOS classroom. Results showed areas of improvement in co-writing and a perception among students that co-writing was helpful. The paper aims to contribute to greater understanding and improved co-writing delivery and practice for ESL students and practitioners.