This paper aims to share the experiences during online teaching of two different project-based learning courses at Hamburg University of Technology (TUHH) during the COVID-19 (Corona) pandemic 2020. The success of project-based learning courses relies on how freely and openly students can discuss their task-oriented problems in small teams. The most effort-intensive part of the online teaching of project-based learning is to enhance collaboration among students. This paper highlights the challenges we faced, how we overcame some of these challenges, and our lessons learned. Additionally, the results from a student survey conducted during the semester show the students’ feedback on online teaching.