Prior studies have examined offshore sailing and energy strategies using accurate total energy expenditure (TEE) measurement in free-living conditions. However, no research has studied energy and water requirement during dinghy class sailing such as an Olympic event with concentrated training. This study aimed to investigate the TEE, physical activity level (PAL), and water turnover (rH2O) of collegiate dinghy sailors in a training camp using the doubly labeled water (DLW) method. Eleven dinghy sailing collegiate athletes (9 males and 2 females) participated. The DLW method was used to determine the participants' TEE and PAL over 8 days (6 training, 2 non-training days). Participants trained approximately 7 h/day on water. Body fat was measured using a stable-isotope dilution method. The rH2O was estimated using deuterium turnover. The mean TEE, PAL, and rH2O were 17.30 ± 4.22 MJ/day (4133 ± 1009 kcal/day), 2.8 ± 0.3 (range, 2.1 to 4.1), and 3.3±0.7 (range, 2.6 to 4.5) L/day, respectively. To our knowledge, this was the first study to use the DLW method to determine TEE, PAL, and rH2O as references for competitive dinghy sailors in a spring training camp. Our results may serve as a reference to assist competitive dinghy sailors in determining their required nutritional support.