Situation awareness (SA) of the officers of watch (OOW) was evaluated. The goals of the situation awareness evaluation was to compare the SA of inexperienced OOW and the SA of experienced OOW. A full mission bridge simulator was used to measure their SA ability. As a result, there were some differences in acquiring information related to given situation between inexperienced OOW and experienced OOW. The inexperienced OOW generated false alarm and miss error. However, there was no differences in level 2 and level 3 of SA. To support insufficient SA ability of the inexperienced OOW, some training programs on visual search is required and interface of ARPA radar should be developed to control the radar as possible as quickly under time pressure.