BACKGROUND: Kingdom of Saudi Arabia (KSA) demographics are also changing with the increase in life expectancy in the country and the rise in the number of older Saudi Arabians. Saudi Arabia has a higher rate of physically inactive people, and most of them are between the ages of 55-64. Walking is one of the most prevalent forms of physical activity in Saudi Arabia and the study showed that most people prefer walking for recreational and health benefits. Therefore, the purpose of the proposed study is to compare the effects of supervised group-based walking and non-supervised individual-based walking interventions on frailty, cognitive function and quality of life among inactive older adults in Saudi Arabia. METHOD: This study will apply a three-group (2 intervention groups and 1 control group), double-blinded, randomized controlled trial (RCT) to examine the effect of different forms of walking interventions on Saudi Arabia older adults' frailty, cognitive function and quality of life immediately after a 16-week intervention, as well as the residual effects 12 weeks after completion of the interventions. DISCUSSION: This study aims to determine whether supervised group walking and non-supervised individual walking lead to different effects. Given the limited evidence in the literature regarding Saudi Arabia older adults' physical fitness and health, it is worthwhile to explore the effect of walking, as well as the forms of walking on improving the overall physical fitness and psychological status of older adults in Saudi Arabia. The findings of the current study could also create awareness of the government and the general public in Saudi Arabia of the ageing problems and the effective ways of achieving better intervention results. TRIAL REGISTRATION: The trial is registered at the ClinicalTrials.gov PRS (Trial ID: NCT05151575; Date of first posted: 12/07/2021).