This paper aims to examine the applicability of the CDIO approach to online Project-Based Learning (PBL). Particularly, focusing on students’ online communication skills, we examine the effectiveness of forming ‘ba’ for enhancing online communication skills. Due to COVID-19, our education has been forced to change a lot. Many classes were held online from 2020 to 2021. This paper introduces two examples of online PBL activities to discuss how those activities helped students to enhance online communication skills. To consider students’ online communication skills, we will introduce the concept of ‘ba’, a concept that has been studied in organizational science. ‘Ba’ is a kind of space in which relationships are forge and human interactions take place. We also discuss the effects of applying the CDIO framework to those activities. By considering these activities conducted using the CDIO framework and considering from the perspective of the concept of ‘ba’, it was revealed that the CDIO approach helped students improve their online communication skills.