We use data from nationally representative time-use surveys to compare and contrast lone and partnered mothers’ childcare time in four countries with different social norms and policy orientations towards mother-care and work–family reconciliation: Australia, the United States, France, and Denmark (N = 8,031). We decompose time with children into primary activity care tasks: (i) physical care, (ii) talk-based interactive activities, (iii) accompanying children, and also measure (iv) additional time spent with children net of specific care activities. We find that, on average, mothers in Australia and the United States spend substantially longer each day with children net of specific care activities than mothers in France and Denmark, but that primary activity care tasks are relatively uniform cross-nationally. In France and the United States, lone mothers spend less time with their children in total than partnered mothers. Gaps are widest in the United States, where, uniquely, lone mothers also do less primary activity of child care than partnered mothers.