Yellow-throated Toucan occurs from Central America south to central Peru. The northern population ("Chestnut-mandibled Toucan", swainsonii) is a locally common resident from southeastern Honduras south through Nicaragua, Costa Rica, and Panama, western and northern Colombia, and western Ecuador. For the most part, it is a lowland-dwelling bird (rarely occurring above 1000 m), but has been recorded up to 2000 m in Colombia (Haffer 1974). In western Colombia and Ecuador, it is chiefly found in the western foothills and Chocó, but in Colombia it also occurs in the Cauca and Magdalena valleys, as far east as eastern Antioquia (Hilty and Brown 1986). Determination of its status in the middle and upper Magdalena valley of Colombia is complicated by heavy deforestation (Stiles et al. 1999). The species also occurs ("Black-mandibled Toucan", abbreviatus and ambiguus) in lower montane forests and foothills from northwestern Venezuela south through Colombia and Ecuador to Peru. In Colombia and Venezuela, it is found on both slopes of the Eastern Cordillera, becoming restricted to the east slope in Ecuador and Peru (Short and Horne 2001, Hilty 2003, Donegan et al. 2007). An isolated population also occurs in the coastal range of northern Venezuela (Hilty 2003).
"Black-mandibled Toucans" occur at relatively high elevations compared to other Ramphastos. It typically occurs between 800-2000 m but may reach lower elevations in areas such as the Maracaibo Basin, where it has been recorded as low as 100 m. Part of why it inhabits this narrow altitudinal range and not the adjoining lowlands may have to do with competition from White-throated Toucan (R. tucanus), which replaces "Black-mandibled" at lower elevations; where White-throated is absent (e.g., the Maracaibo Basin), "Black-mandibled" thrives at lower elevations (Haffer 1974). The two "Black-mandibled" subspecies, ambiguus and abbreviatus, replace each other on opposite slopes of the Eastern Cordillera (Donegan 2007), and are "unlikely to have any permanent zone of contact due to the high ridgeline of the East Andes in this region". Subspecies ambiguus lives on the eastern slope, whereas abbreviatus inhabits valleys and foothills between the Central and Eastern Cordilleras, extending east as far as the middle Magdalena valley (where it may meet with swainsonii) (Hilty and Brown 1986).