Aquatic High Intensity Interval Training Deep water running (AHIIT-DWR) has the potential to improve cardiometabolic health and cognitive psychological responses, offering a reduced risk of injuries and greater affordability for inactive elderly women. Purpose: To investigate the effects of an 8-week AHIIT- DWR intervention compared to land-based HIT training (LHIIT) on cardiometabolic health, cognitive and psychological outcomes in inactive elderly women. Methods: Seventy inactive elderly women aged 60 or above were randomly assigned into two groups: AHIIT-DWR and LHIIT. The AHIIT-DWR group engaged in DWR sessions comprising 30-minutes of interval training, consisting of ten 2-minute exercise bouts at 80-90% of their maximal heart rate (HR max), with 1-minute active recovery at 70% HR max between bouts, for two sessions per week, for 8 weeks. The LHIIT group performed treadmill running at the same intensity. Results: Both groups showed similar cardiovascular fitness, maximal aerobic capacity (VO2max), maximal HR and respiratory exchange ratio (RER) improvement (p > 0.05), while AHIIT-DWR showed a significant improvement in aerobic capacity minute ventilation (VE), metabolic equivalents (METs) and O2 pulse (p < 0.05) over the 8- week intervention. Both AHIIT-DWR and LHIIT significantly decreased triglycerides, total cholesterol. HDL, LDL post intervention (p < 0.05). No significant group differences were observed for cognitive function assessed by MMSE and MOCA, (p > 0.05). Both groups showed similar enjoyment levels, self-efficacy scores and high adherence rates (>90%). Conclusions: Our study suggests that AHIIT-DWR can elicit a similar improvement in cardiorespiratory health, metabolic blood markers, cognitive function assessed by MMSE and MOCA and psychological responses as LHIIT in inactive elderly women.