This study examined the career adaptability model of the career construction theory (CCT, Savickas, 2021) using data collected from two time points and measures that covered the inter-related domains of career and life planning. Participants were high school students (470 women and 338 men) from 14 secondary schools in Hong Kong. Students completed the adaptive readiness (interests and competence flexibility) and adaptability resources (Career Adapt-Ability Scale, CAAS) measures in their sophomore or junior year of study (Time 1), and the adapting responses (life-skills competencies) and adaptation results (presence of life purposes, career decision-making difficulties) measures at the end of their senior year (Time 2). Findings from SEMs suggested a good fit of the data with the career adaptability model. Interest and competence flexibility, adaptability resources from Time 1 contributed directly and indirectly to the prediction of life-skills competencies, the presence of life meaning, and decision-making preparedness in Time 2 as hypothesized. Interest and competence flexibility were instrumental in activating adaptability resources and maintaining movement through transitions, and the CAAS and life skill measures were mediating variables in the adaptability process. The SEM using the CAAS dimensions revealed that the concern and the confidence subscales were involved in the sequence of direct and indirect effects. Results demonstrated that the adaptability model could be used to understand the transition experience of high school students who were facing rapid social changes. Conceptual, practice, and research implications were discussed. • The career adaptability model was valid for Chinese senior high school students. • Competence flexibility with clarity of interests facilitated career adaptability. • Adaptability resources were positively associated with life skills competencies. • Adaptability resources was positively associated with presence of life meaning. • The career adaptability model could inform career guidance for students in transitions.