Abstract Drill string vibrations (torsional, axial, and lateral uncontrolled movements) can create issues with equipment, drilling performance and wellbore quality. With respect to equipment, prolonged excessive drill string vibration exposure can lead to fatigue failure such as drill string ‘twist off’, downhole tool breakage, shorter mean time between failure (MTBF) for measurement-while-drilling (MWD)/logging-while-drilling (LWD), and, in general, for directional drilling components. In rotary steerable drilling, a moderate to high drill string vibration can result in poor directional control, reduced penetration rate, and loss of time. This can result from reactive changes in drilling parameters intended to reduce detected drill string vibrations. Wellbore quality can suffer if the vibrations cause the bit to not drill a smooth borehole. Simultaneous drilling and hole enlargement are sometimes associated with drill string vibration because of complex bottomhole assembly (BHA) dynamics involved in creating two hole sizes. Sources of drill string vibration during hole enlargement can be the drill bit, hole enlargement tool, or BHA. Mitigation of drill string vibration with respect to hole enlargement tools is of major interest because this can lead to reduced drilling costs, longer tool life, and improved wellbore quality. This paper discusses specific expandable hole enlargement tool technologies that contribute to a reduction of vibration levels. Case history data is used to demonstrate these technologies, which have been shown to minimize drill string vibration during drilling and simultaneous enlargement operations, leading to the successful completion of well objectives.