Successful navigation can require realising the current path choice was a mistake and the best strategy is to retreat along the recent path: ‘back-tracking’. Despite the wealth of studies on the neural correlates of navigation little is known about back-tracking. To explore the neural underpinnings of back-tracking we tested humans during functional magnetic resonance imaging (fMRI) on their ability to navigate to a set of goal locations in a virtual desert island riven by lava which constrained path that could be taken. We found that on a subset of trials, participants spontaneously chose to back-track and that the majority of these choices were optimal. During back-tracking, activity increased in frontal regions and the dorsal anterior cingulate cortex, while activity was suppressed in regions associated with the core default-mode network. Using the same task, magnetoencephalography (MEG) and a separate group of participants we found that power in the alpha band was significantly decreased immediately prior to such back-tracking events. These results highlight the importance for navigation of brain networks previously identified in processing internally-generated errors and that such error-detection responses may involve shifting the brain from default-mode states to aid successful spatial orientation.