This exploratory action research study aims to understand the challenges that a group of pre-service teachers faced while participating in an undergraduate course unit introducing Content and Language Integrated Learning (CLIL) teaching in an online context (Cycle 1), and the way in which they implemented plans of action (Cycle 2) to address issues uncovered in Cycle 1. The study found that the pre-service teachers experienced problems applying appropriate English teaching approaches to promote their pupils' communicative competence. Four measures were applied in Cycle 2, such as restructuring the training-teaching module, reinforcing the concept of English as a lingua franca to promote students' communicative skills, selecting authentic materials to enhance students' motivation, and obtaining administrative support to resolve technological problems. The results from English proficiency tests showed that the pupils improved their reading and listening skills in Cycle 2. Although the actions taken in Cycle 2 were focused on improving pupils' English abilities, these actions also had the effect of enhancing the pre-service teachers' CLIL pedagogical concepts, such as the translanguaging approach. The study provides a detailed description of CLIL teaching with online storybooks and adds to the body of much-needed studies of CLIL in practice, especially in the Asian context.