OBJECTIVE: To investigate the age-related differences in the contributions of the domains of physical activity (PA) for men and women in Scotland who met the current PA guidelines or who were insufficiently active. METHODS: We analysed data from the 2013 Scottish Health Survey (4885 adults (≥ 16 years)). Average weekly minutes of moderate or vigorous PA (MVPA) and the relative contributions to total MVPA were calculated for the domains of: walking, cycling, domestic, leisure, occupational, outdoor, non-team sport, team sport, and exercise & fitness. We performed linear regression analyses to assess differences by 10-year age group, stratified by sex and activity status (1-149 or ≥ 150 min of MVPA per week). These were repeated excluding occupational activity due to concerns with its measurement. RESULTS: For the 64.3% of the sample that met the guidelines, occupational activity was the most prevalent domain accounting for 18-26% of all MVPA for those under 65 years. When excluded, there was no age-related decline in total MVPA (p > 0.05). For the 18.6% of the sample that reported 1-149 min of MVPA per week, domestic activity was the most prevalent domain. Across both sexes and activity statuses, exercise & fitness declined with age and walking was most prevalent in the oldest age group. CONCLUSION: The domains in which adults in Scotland undertake MVPA vary by age group. Policies designed to increase PA should take this into account. Our findings challenge current thinking on age-related changes in activity, with the exclusion of occupational activity mitigating any age-related decline in MVPA.