Driving into floodwater is a leading cause of fatal and non-fatal drowning during times of flood. The present research aimed to understand drivers’ beliefs and intentions in relation to driving into floodwater caused by flash floods in an urban area (Newcastle City, Australia), using the theory of planned behavior as a framework. The study (N = 217) used a survey-based design to identify the psychological processes (attitude, subjective norm, perceived behavioral control, planning, moral norm) underpinning drivers’ intention to avoid driving into floodwater in Newcastle; and to concurrently investigate the potential effects of a brief planning intervention on drivers’ willingness to drive into floodwater in Newcastle. The structural equation model explained 49% of the variance in intention to avoid driving into floodwater in Newcastle, with subjective norm, perceived behavioral control, and planning each significant independent predictors of drivers’ intention to avoid driving into urban floodwater in Newcastle. Paired samples t-tests revealed participants’ willingness to stay at their location and not drive if a flood alert was received, and willingness to drive into floodwater when there is perceived pressure from other drivers, significantly changed after a brief planning intervention. These findings can inform intervention targets and development of prevention strategies targeting personal mitigation measures, particularly in the context of driver behaviour during flash flooding in an urban area.