The Ohio State University's Center for Human-Animal Interactions Research and Education (CHAIRE) and the Columbus Zoo and Aquarium (CZA) have partnered for a longitudinal study to assess the welfare of their California sea lions (Zalophus californianus) as they undergo a relocation process from a temporary facility to permanent habitat at CZA. Presented here is the phase of the larger study aimed at measuring the animals' welfare throughout the process of transporting the animals between facilities. Given the frequency with which marine mammals are transported between institutions, and there are known stressors associated with transport, salivary cortisol concentrations (SCC) were measured to assess the animals' welfare throughout this process. We found that SCC was highest post-transport (21.503 ± 3.318 nmol/L, P= .0001), although only significantly different from pre-transport (P = .0003) not the transport period (P = .0856). There was no effect of sex (P = .877) or age (P = .549) on SCC. We also established a range of SCC for California sea lions to be 12.37 ± 18.88 nmol/L, a novel contribution to marine mammal physiology. These findings offer evidence that measurement of cortisol concentrations through saliva is feasible and valuable in this species. The elevated SCC post-transport may indicate a response to the novelty of staff and environment the animals were exposed to upon arrival at the permanent habitat, although it is important to note it cannot be conclusively determined whether this response is positive or negative with respect to welfare. In order to better evaluate the welfare implications of this finding, results from this phase will be compared to the longitudinal measures of welfare from the comprehensive study, offering a more holistic view of the impact of transport on these animals' welfare. These findings will contribute to the growing field of marine mammal welfare science and hopefully inform future transport and relocation practices to minimize potential consequences to animal welfare.