Participants: In this study, 40 18-23yr olds took part in three Prospective Memory (PM) tasks. A questionnaire distinguished two groups based on the frequency of their smartphone usage: these were ‘Low Users’ (16) and ‘Higher Users’ (24). Design: The study was a 2x4 between-subjects Multivariate Analysis of Covariance (MANCOVA) design. The research had three objectives: the first was to determine the accuracy of self-reported PM failures; the second was to observe any differences in PM performance between lab-based tasks and naturalistic-based tasks; and the third and principal aim of the study was to explore whether the frequency of smartphone usage had an effect on PM. Methods: The Prospective Retrospective and Memory Questionnaire (PRMQ) was used as a self-reported measure of the frequency of everyday memory failures. The objective PM was measured across 3 tasks: one event-based lab task (Smiley Face Task); one time-based lab task (tapping a stopwatch every 1 minute); and one task in a real-world setting, which involved participants texting the experimenter at a specified time over a 5-day period. Results: The results found participants’ subjective memory scores shared no relationship with objective memory scores on the two time-based tasks. A significant correlation was found between subjective memory and the event-based task, but subjective memory only explained a small proportion of the variance (r2= .12). Participants were significantly more successful on the lab-based task than the real-world task t(31)= 2.095, p< .05. Smartphone usage was found to have a non-significant effect on PM. Conclusion: The findings suggest three things: PRMQ is not a reliable indicator of PM; lab-based tasks are appropriate for student samples; and the absence of an effect of smartphone use on PM supports McDaniel & Einstein’s automatic model of PM (2007b).