Implicit motor sequence learning is necessary to perform daily activities and is susceptible to age-related deficits. We examined how aging affects the learning of deterministic and probabilistic sequences assessed using the serial reaction time task and related variants. Both young and older adults demonstrated within-session learning of both sequence types, with some impairment in older adults at higher complexity levels. Young adults generally exhibited between-session offline learning of deterministic sequences, whereas older adults did not. Studies on offline learning of probabilistic sequences were limited and less consistent. These differences may be attributed to age-related changes, but may also be due to methodological variations across studies, particularly in the calculation of offline learning. Older adults may perform better in less complex tasks, require more exposure to the sequence, and employ alternative strategies (e.g., declarative knowledge) for learning. Recent research in young adults has found micro-online (improvements during task performance) and micro-offline (improvements after short breaks) learning within an implicit motor sequence learning session, but these processes are currently unexplored in older adults. Future research may investigate optimal break duration and frequency to better understand the temporal dynamics of implicit motor learning processes, both within and between sessions, and how they are impacted by aging.