Objective To test whether there is an association of social class (im)mobility in childhood and adulthood with absolute rates of adult participation in sport and exercise.

Design Secondary analysis of the 2003 Scottish Health Survey.

Participants 2770 Scottish men and women aged 35–54.

Results The highest age- and sex-adjusted rate of sport and exercise was seen among those who were in the highest social class in both childhood and adulthood (62.8%), while those in the lowest social class at both stages had the lowest rate at 25.8%, 37% points lower. This gap was wider than if the assessment of participation had been based solely on childhood or adult social class. The upwardly mobile had a higher rate than their class of origin in childhood but a lower rate than their class of destination in adulthood. The downwardly mobile had a lower rate than their class of origin but a higher rate than their class of destination.

Conclusion There are major absolute differences in participation in sport and exercise associated with social class (im)mobility that will be important to understand in order to improve population health and to reduce health inequalities.