With courses being moved online because of COVID-19, there is a need for exploring innovative and effective online teaching models. This article firstly introduces the pedagogical practice of the fully online flipped instruction (FOFI), an adaptation of the flipped classroom approach that is employed completely online, which has been adopted for EFL undergraduates in China during COVID-19 based on video conferencing and prior experience in Small Private Online Course (SPOC)-based flipped classrooms. A questionnaire and two focus group discussions were conducted to investigate students' perceptions of this model. The data were collected and analysed quantitatively and qualitatively, which reveal their positive perception concerning teacher instruction, varied interaction, and multifunctional platforms. However, less motivated students hold contrasting opinions on learning platforms and online interaction. This study also demonstrates that students' interests, self-regulation, and learning environment significantly affect learner experience and learning outcomes. The implications for the implementation of FOFI are further discussed.