Physical activity is safe and feasible for individuals with metastatic cancer and may support symptom management. We investigated the extent to which individuals with metastatic cancer are meeting the World Health Organisation (WHO) moderate-vigorous physical activity (MVPA) guideline, factors associated with meeting the guideline, and perceptions about physical activity and receiving physical activity advice. Data were from UK adults with metastatic breast, prostate, or colorectal cancer who completed the Healthy Lifestyle After Cancer survey (N = 588). Self-reported clinical, demographic, and physical activity (Godin Leisure-Time Exercise Questionnaire) data were collected. Logistic regression models assessed whether clinical and demographic factors were associated with meeting the MVPA guideline. Most (59%) individuals with metastatic cancer were not meeting the WHO guideline of 150min of MVPA per week. Adjusting for cancer type, the odds of meeting the MVPA guideline were lower for unemployed individuals (OR = 0.47, 95% CI = 0.23-0.77) and ethnic minorities (OR = 0.44, 95% CI = 0.22-0.89), but higher for those with a university education (OR = 1.89, 95% CI = 1.0-3.57). Most (63.5%) participants felt they should be doing more physical activity. However, 70.1% did not receive any physical activity advice or support, despite 73.6% wanting to receive it. People with metastatic cancer may need further support to address inadequate levels of physical activity. The differences observed between demographic sub-groups suggest this may be more beneficial for those less likely to engage in physical activity. Individuals with metastatic cancer are likely to benefit from increased physical activity support, which considers the needs of diverse demographic groups.