<p>Navigating a dynamic world requires rapidly updating choices by integrating past experiences with new information. In hippocampus and prefrontal cortex, neural activity representing future goals is theorized to support navigational planning. However, it remains unknown how prospective goal representations incorporate new, pivotal information. Accordingly, we designed a navigation task that precisely introduces new information using virtual reality, and we recorded neural activity as male mice flexibly adapted their planned destinations. Here we show that new information triggered increased hippocampal prospective representations of both possible goals; while in prefrontal cortex, new information caused prospective representations of choices to rapidly shift to the new choice. When mice did not adapt, prefrontal choice codes failed to switch. Prospective codes were dependent on the amount of behavioral adaptation needed; the new goal arm was represented more strongly when animals needed to change their behavior more. Thus, we show how prospective codes update with new information to flexibly adapt ongoing navigational plans.</p>