We performed a prospective crossover study to determine the cervical spine immobilization and comfort level of healthy subjects on a full-body vacuum splint in comparison with a standard backboard, with and without cervical spine collars. Twenty-six healthy volunteers were immobilized on a backboard (BB) and a full-body vacuum splint (VS), both with and without a cervical collar (CC). Pre- and post-immobilization cervical spine range-of-motion measurements were made using an electronic digital inclinometer and a standard handheld goniometer. Subjects were also asked to subjectively grade their immobilization and discomfort both overall and in seven specific body regions. No statistically significant difference was found between the VS+CC and the BB+CC for flexion and rotation, although the VS+CC combination provided significantly superior immobilization to the BB+CC for extension and lateral bending. The VS alone, in all cases except extension, provided superior immobilization to the BB alone. A statistically significant difference in subjective perception of immobilization was noted, with the BB being less effective than the other three alternatives and the VS+CC providing the best immobilization. A significant difference in overall comfort and occipital region comfort, favoring the vacuum splint, was found. In conclusion, the vacuum splint is an effective and more comfortable alternative to the background for cervical spine immobilization.