Understanding how dental attendance evolves throughout life can inform targeted preventive health care policies by identifying key moments when people are more or less likely to seek dental care. Trajectory modeling of age and time trajectories takes a life course approach to understanding dental attendance, offering insights into both developmental perspectives (e.g., life stages) and structural perspectives (e.g., social position and health care systems) throughout the life course. This study used group-based trajectory modeling to identify (1) the age trajectories of dental attendance among Australian adults from young adulthood to retirement age and (2) the distinct time trajectories of dental attendance among Australian working-age adults. Data from the Household, Income and Labour Dynamics in Australia (HILDA) study was used to fit 2 trajectory models (age and time based). Age trajectories were fitted for individuals aged 15 to 64 y using dental attendance data from 3 time points: 2009, 2013, and 2017. Time trajectories were fitted for working-age adults (24-54 y) using data from 2009 to 2017 and descriptively analyzed by social characteristics. Dental attendance was classified as frequent (less than 2 y since the last visit) or infrequent (2 y or longer). Two distinct age trajectories emerged among participants (