Objectives: Emergency cricothyroidotomy is the final approach to establishing a secure airway. The procedure is acute and highly infrequent, making it difficult to achieve and maintain competence in the clinic. Simulation-based training in emergency cricothyroidotomy is effective but it is unknown how often training should be repeated to maintain skills. This study aimed to assess novices’ retention of technical skills in emergency cricothyroidotomy after completing SBT. Methods: Novices in emergency cricothyroidotomy completed a structured, simulation-based training program and were randomized to retention tests after 1, 3, or 6 months. Participants completed two emergency cricothyroidotomy tests at end-of-training and follow-up retention testing. Test performances were video recorded and evaluated by two experienced blinded raters using a structured assessment tool. Differences in the performances and the pass/fail rates were analyzed. Results: Eighty-two medical students from two different Danish universities were included from April 2021 to February 2022. Paired t-tests showed skills decay significantly after 1 month (mean loss 6.7 points, p < 0.001). The mean loss of points, representing the difference in global score points, from the end-of-training to retention test was 6.7 points (95% confidence interval [CI] 4.5–8.8) for the 1-month group, 8.2 points (95% CI 5.8–10.0) for the 3-months group, and 9.9 points (95% CI 8.1–11.7) for the 6-months group. Six participants in both the 1-month group (23.1%) and the 3-month group (24%) passed the first retention test, but no one in the 6-months group had a passing performance. Conclusions: Novices’ technical skills performance in emergency cricothyroidotomy decay significantly already after 1 month. This initial loss of skill seems to be stable until 3 months, after which there is a further significant loss of skills. Recurring training should be implemented for the benefit of patient safety and outcomes.