Seamless language learning promises to be an effective learning approach that addresses the limitations of classroom-only language learning. It leverages mobile technologies to facilitate holistic and perpetual learning experiences that bridge different locations, times, technologies or social settings. Despite the emergence of studies on seamless language learning, there is a lack of instruments specifically designed to measure students' motivation and learning strategies in such technology-enhanced learning environments. This study aimed to develop and validate an instrument, namely, the Mobile-Assisted Seamless Chinese Learning Questionnaire (MSCLQ), to measure students' motivation and the learning strategies they use in a seamless learning environment. Confirmatory factor analyses (CFA) were conducted to validate the psychometric properties of the instrument. Subsequently, structural equation modeling (SEM) was conducted to examine how students' intrinsic value and self-efficacy for learning Chinese language predicts their perception of the various dimensions of meaningful seamless learning. The findings indicated that the MSCLQ is a valid and reliable questionnaire. Moreover, it was also found that students' motivation predicted the learning strategies they used in a seamless learning environment. Implications are discussed.