Tanzania is one of the world’s leading nations in terms of wildlife conservation, with rich and diverse wildlife resources. Game controlled areas in Tanzania are used for wildlife conservation and most of them were set aside when human populations were low and global climate was stable. Under the climate change scenario realised for Tanzania for the next few decades, a 10% increase in annual inflow is predicted at the Kilombero Ramsar site. This may have varied impacts on the wildlife populations with consequences for the potential direct economic values from wildlife hunting. The current study assessed how rainfall may influence wildlife populations and their contribution to the national economy. Data was collected from discussions with game officials, literature searches, field observations and data was recorded for weather and hunting licences. We established a rainfall pattern based on trends observed over 40 years (1968–2008), and its correlation with wildlife outtake by both tourist and local hunters. The mean annual rainfall was 1,600 mm, with a probability of 0.90 of receiving (100 ≤ 300) of the mean annual rainfall especially for March and April point rainfall. Increased inflow of water is likely to be exacerbated by inflow from surrounding catchments. There were a total of 258 local and 78 tourist hunters respectively in the period from 2001 to 2008. There was a positive correlation between the number of animals hunted per species and point annual rainfall for buffalos, reedbuck, hippos, puku, warthog, crocodiles and hartebeest. Conversely, the availability of game birds declined with increased point rainfall. This would mean that revenues from buffalo, reedbuck, hippos, puku, warthog, crocodiles and hartebeest are likely to increase or remain the same with increasing point annual rainfall. On the other hand, hunting revenues from game birds is likely to decrease with point annual rainfall. The predicted hydrological change in the Kilombero River is likely to affect wildlife populations and the contribution of hunting industry to national earnings. Thus climate adaptation measures need to be instituted in order to accommodate climate-induced economic loses.