The article discusses the importance of physical activity in promoting healthy ageing and preventing frailty among older adults. Despite the well-publicized benefits of physical activity, most older people in the United Kingdom do not meet the recommended minimum levels of physical activity. The sedentary lifestyles common in older age can lead to premature onset of ill health, disease, and frailty. Local authorities have a responsibility to promote physical activity among older adults, but encouraging regular activity at the population level is challenging. The physiological rationale for physical activity, risks of adverse events, and societal and psychological factors are discussed to inform public health initiatives. Regular physical activity is shown to be safe for both healthy and frail older adults, reducing the risk of major cardiovascular and metabolic diseases, obesity, falls, cognitive impairments, osteoporosis, and muscular weakness. However, participation in physical activities remains low among older adults, particularly those in less affluent areas. Encouraging older adults to increase their activity levels can be achieved through clinician, family, or friend influence, keeping costs low, making activities enjoyable, facilitating group-based activities, and raising self-efficacy for exercise.The article discusses the importance of physical activity in promoting healthy ageing and preventing frailty among older adults. Despite the well-publicized benefits of physical activity, most older people in the United Kingdom do not meet the recommended minimum levels of physical activity. The sedentary lifestyles common in older age can lead to premature onset of ill health, disease, and frailty. Local authorities have a responsibility to promote physical activity among older adults, but encouraging regular activity at the population level is challenging. The physiological rationale for physical activity, risks of adverse events, and societal and psychological factors are discussed to inform public health initiatives. Regular physical activity is shown to be safe for both healthy and frail older adults, reducing the risk of major cardiovascular and metabolic diseases, obesity, falls, cognitive impairments, osteoporosis, and muscular weakness. However, participation in physical activities remains low among older adults, particularly those in less affluent areas. Encouraging older adults to increase their activity levels can be achieved through clinician, family, or friend influence, keeping costs low, making activities enjoyable, facilitating group-based activities, and raising self-efficacy for exercise.