Recurrent ankle sprains can be reduced by following a neuromuscular training (NMT) program via a printed Booklet or a mobile application. Regarding the high incidence of ankle sprains, cost-effectiveness regarding implementation can have a large effect on total societal costs. In this economic analysis, we evaluated whether the method of implementing a proven effective NMT program using an App or a Booklet resulted in differences in injury incidence rates leading to costs and hence to differences in cost-effectiveness. In total, 220 athletes with a previous ankle sprain were recruited for this randomized controlled trial with a follow-up of 12 months. Half of the athletes used the freely available “Strengthen your ankle” App and the other half received a printed Booklet. After the 8-week program, athletes were questioned monthly on their recurrent injuries. Primary outcome measures were incidence density of ankle injury and incremental cost-effectiveness ratio (ICER). During follow-up, 31 athletes suffered from a recurrent ankle sprain that led to costs resulting in a hazard ratio of 1.13 (95% CI: 0.56-2.27). The incremental cost-effectiveness ratio of the App group in comparison with the Booklet group was €361.52. The CE plane shows that there was neither a difference in effects nor in costs between both intervention methods. This study showed that the method of implementing the NMT program using an App or a Booklet led to similar cost-effectiveness ratios and the same occurrence of recurrent injuries leading to costs. Both the App and the Booklet can be used to prevent recurrent ankle injuries, showing no differences in (cost-) effectiveness at 12-month follow-up.