Prospective memory (PM) refers to remembering to perform a previously planned action at the appropriate time or in the appropriate context. The present study investigated the effects of individual differences in age and trait anxiety on PM performance in 3-5- and 5-7-year-olds. Two types of PM measures were used: an event-based task, requiring ongoing activity interruption across two conditions (with/without memory aid), and an activity-based task, requiring PM action implementation after the main activity was finalized. On the event-based PM task, we found that: all children benefited from the external memory aid; the 5-7-year-old group outperformed the 3-5-year-olds; and higher levels of anxiety negatively affected only the younger age group. On the activity-based PM task, we found no significant age-group differences, while higher anxiety negatively predicted children's PM performance. Findings support and extend the literature on early PM development, revealing the benefits of external cueing and the potential detrimental effects of anxiety.