SCUBA diving requires a high level of cognitive functioning given the task loading that divers face while underwater. Divers must be able to remember skills from their training and remain vigilant in order to successfully complete their dive. However, many divers report poor memory and attentional skills while underwater, especially as the depth of the dive increases. This is due to the narcotic effect of the inert gas nitrogen at high partial pressures. Several studies have documented both long- and short-term neurological and cognitive effects of diving including long-term changes in brain morphology and short-term changes in cortisol levels, and memory and attentional control following a dive. Few studies have measured cognitive impairment during a dive and no studies have directly compared memory and attentional deficits as a function of dive depth. Here we seek to measure participant cortisol levels before and after a dive and performance on memory and attention tasks during a dive at both shallow (20-30 ft) and deep (80-90 ft) depths. Results of the study can be used to help further refine diving procedures to ensure optimal cognitive functioning during a dive.