Individuals often choose between remembering information using their own memory ability versus using external resources to reduce cognitive demand (i.e. ‘cognitive offloading’). For example, to remember a future appointment an individual could choose to set a smartphone reminder or depend on their unaided memory ability. Previous studies investigating strategic reminder setting found that participants set more reminders than would be optimal, and this bias towards reminder-setting was predicted by metacognitive underconfidence in unaided memory ability. Due to the link between underconfidence in memory ability and excessive reminder setting, the aim of the current study was to investigate whether metacognitive training is an effective intervention to a) improve metacognitive judgment accuracy, and b) reduce bias in strategic offloading behaviour. Participants either received metacognitive training which involved making performance predictions and receiving feedback on judgment accuracy, or were part of a control group. As predicted, metacognitive training increased judgment accuracy: participants in the control group were significantly underconfident in their memory ability, whereas the experimental group showed no significant metacognitive bias. However, contrary to predictions, both experimental and control groups were significantly biased toward reminder-setting, and did not differ significantly. Therefore, reducing metacognitive bias was not sufficient to eliminate the bias towards reminders. We suggest that the reminder bias likely results in part from erroneous metacognitive evaluations, but that other factors such as a preference to avoid cognitive effort may also be relevant. Finding interventions to mitigate these factors could improve the adaptive use of external resources.