To determine the effects of hydrotherapy and land-based exercises on functional mobility and quality of life among patients with knee osteoarthritis. [Participants and Methods] We conducted a randomized controlled trial with knee osteoarthritis patients randomly allocated into land-based (n=17) and hydrotherapy groups (n=17). The Time-Up and Go (TUG), Five Times Sit-to-Stand (5STS), Stair Climbing Test (SCT), and Quality of Life by questionnaires including the Modified Western Ontario and McMaster Universities Osteoarthritis Index questionnaire Thai version (Thai WOMAC) were assessed at baseline and 6 weeks. The World Health Organization Quality of Life BREF Thai version (WHOQOL-BREF-THAI) questionnaire were assessed at baseline and six weeks and 6 months. [Results] There was no significant difference in outcomes between the groups after 6-weeks and 6-months of follow-up. After 6 weeks, Thai WOMAC score improved in both groups. Only 5STS was improved in the land-based group, while the hydrotherapy group showed significant TUG, 5STS, and SCT improvement. Furthermore, only hydrotherapy showed significant improvement in WHOQOL-BREF-THAI scores in the mental, social, quality of health, and total domains after six months. [Conclusion] Both exercises equally improved functional mobility and quality of life. Hydrotherapy and land-based exercise could improve functional mobility and quality of life in patients with knee osteoarthritis.