Disposable surgical face masks are designed to block the airborne transmission of infectious viruses between patients and healthcare personnel; however, there are limitations to a surgical mask's ability to prevent transmissions because the mask does not provide an airtight seal around the face. This study focuses on the design and development of a custom mask frame, using individuals' three-dimensional (3D) facial scans, to improve the seal of the existing surgical masks. Three participants' facial scans with a wide range of facial dimensions were collected using a 3D hand-held scanner. During design, the contact area between the custom frame and the wearer's skin was determined based on the individual's 3D facial shape. To evaluate the effectiveness of the airtight seal, a qualitative fit (smell/taste) test kit and thermal imaging camera were utilized. When the participants wore the surgical masks without the customized mask frames, the participants smelled the saccharine scent from the test kit. However, while wearing the surgical masks fitted with the custom mask frame that held the mask in place, none of the participants could smell the scent. In addition, thermal images showed ambient temperature changes in the surgical mask suggesting air leakage around the boundary of the mask while the subject was inhaling and exhaling. With the mask frame, thermal images confirmed the effectiveness of the custom frame to block the inflow/outflow of air potentially carrying the virus. The results indicate that the custom-built mask frames are effective in providing a proper and much improved seal compared to a surgical mask without the frame. The developed custom mask frame will be particularly beneficial for frontline medical staff members who treat patients with infectious viruses transmitted through aerosols as part of their PPE.