Despite significant evidence that age is an important factor in homelessness, life course considerations have not been systematically incorporated into the most influential theories of the factors that heighten the risk of becoming homeless. To address this oversight, this article examines variations in the risk of transitioning into homelessness among single adults in Dublin, Ireland. Consideration is given to how these transitions are shaped by the interaction between life course stage and changing personal circumstances, experiences, and relationships. It reveals that while some triggers of homeless, such as leaving institutional or private rented accommodation, are common experiences among all age groups, younger and older adults both experience distinct patterns of transition into homelessness. This understanding can help to strengthen the traditionally weak evidence base for homelessness prevention strategies, and in particular inform the design of targeted measures, that address the specific homelessness risks faced by some age groups.