A key challenge in longitudinal studies of the effect of childcare is to find ways to accurately describe constant and changing patterns of care usage. The large U.S. NICHD Study of Early Child Care, for example, used 3-monthly interviews to record the hours of care attended and plot the rise or fall in care quantity over time. However, the majority of studies have relied on ‘snapshots’ of children’s current childcare gathered prospectively across a study, or on a combination of retrospective and prospective data. In this paper we explore the options for using snapshots gathered over time to derive new ways of describing children’s childcare experience. Longitudinal data on children’s childcare arrangements are presented from the first three years of the Child Care Choices study. Annual interviews with the parent generated comprehensive information on the type(s) of care the child received (including long day care centre, family day care, and care provided by grandparents, other relatives, friends, and nannies), the amount in days and hours per week for each care type, and the number of different care arrangements used each week. Of interest in deriving childcare profiles were the ways that care types were combined, such as long day care plus grandparent care, and how these combinations changed or evolved over time. A further interest was developing new methods for incorporating type and hours of care to measure differences in children’s childcare experience.