Background: Transport is an important basis for social participation. Challenges to accessing and using transport for people with intellectual disabilities increase their risk of exclusion and loneliness. Method: Data from a nationally representative study of older people with intellectual disabilities (n = 708) were used to examine longitudinal changes in transport usage and factors associated with using public transport and other travel options. Results: Findings confirmed that this population depends on others for transportation. The most frequently used mode, staff-supported transport, showed no significant longitudinal change. Public transport was secondary, with only moderate continued use between data collection points. Level of intellectual disability most strongly predicted public transport use, while community residence most strongly predicted using public transport to attend work or day programmes. Conclusions: Transport usage is associated with demand and supply factors linked to the person's environment, including having somewhere to go that requires transport and availability of transport options.