Trematode infections cause long-term suffering and debilitation, posing a significant threat to global animal health and production and leading to considerable economic losses. Studies on the epidemiology and control of these infections in Tanzania are limited, and most have been conducted in abattoir settings. The study aims to fill the knowledge gap by determining the prevalence, distribution, and risk factors for trematode infections in domesticated ruminants in two ecological zones of Tanzania. A cross-sectional study was conducted in Lake Victoria and the southern highlands of Tanzania. Rectal fecal samples were collected and examined for Fasciola spp., paramphistomes, and schistosome infections using the sedimentation technique. A total of 1367 domesticated ruminants were sampled and examined for trematode infections. Prevalence of trematode infections was found to be 65.7%. The individual frequency of F. gigantica, paramphistomes, and S. bovis (based on egg morphology only,) was 35.1%, 60.2% and 3.1%, respectively. Adult cattle were more likely to be infected with paramphistomes (AOR: 1.98; 95% CI: 1.40-2.78) and S. bovis (AOR: 8.5; 95% CI: 1.12–64.19) than weaners. It was found that trematode infections in domesticated ruminants are prevalent across Tanzania, therefore effective and community-acceptable prevention and control strategies are highly needed.