International retirement migration (IRM) is hard to quantify yet is an increasingly important element in global migration, especially from more wealthy countries. IRM is driven by demographic, economic and lifestyle factors and is strongly interrelated with tourism flows and destinations. Conventionally seen as a privileged, socio-economically selective migration, it also attracts ‘pension-poor’ people seeking cheaper as well as more satisfying retirement lifestyles in warmer climates and pleasant urban and rural landscapes. Three regional systems of IRM are described: the European north-to-south migration of retirees to places such as southern Spain or rural Tuscany; the American system from North to Latin America, notably Ecuador; and an Asian system focused on Thailand as key destination. Despite systemic shocks such as the global economic crisis and the Covid-19 pandemic, IRM is likely to increase in the future, with new typologies and geographies of movement emerging.