This paper investigates the economic impact of future global change on fishing dependent inhabitants of the Tonle Sap floodplain in Cambodia. We compare the net income from individuals’ current livelihoods to that derived from reallocating their livelihood activities under 4 different scenarios depicting future change. Respondents generally chose to retain their current livelihood strategy under all future scenarios. Less than 10% of those who did change livelihood allocation actually experienced a gain in economic benefits. Those engaged in single livelihoods experienced an average income loss of 18% across all scenarios, compared to 9% for the multi-livelihood group. Respondents’ choices generated the best economic outcome under a status quo scenario, thus suggesting a low capacity to adapt when faced with unfamiliar future scenarios. Our study contributes to identifying and understanding the economic impact of future global changes on fisheries dependent individuals in the Tonle Sap floodplain ecosystem.