Relations between personality profiles, measured by the Personality Characteristics Inventory (PCI), and habitual coping strategies, measured by the Utrecht Coping List (UCL), were investigated in a sample of submarine personnel and office employees. The predictive validity of these instruments were examined for reported stress, health complaints, and salivary cortisone measures during 3 submarine missions. PCI and UCL were completed before the missions, and questionnaires and saliva were collected weekly. The results showed no significant relations between PCI profiles and coping strategies. Interpersonal orientation, achievement motivation, and habitual coping strategies were predictors for coping during the submarine missions. Problem-directed strategies and interpersonal sensitivity combined with strong achievement motivation were related to low indicated stress from social factors (lack of privacy, interpersonal tension, and crowding) and homesickness. The findings suggest that interpersonal characteristics need to be considered in the selection of submariners and personnel for other military settings in which units are exposed to prolonged stress and isolation.