Understanding long-distance dispersal patterns for wide-ranging species is critical to developing effective conservation strategies (Lockwood et al. 2002, Shanks et al. 2003, Gerber et al. 2005, Figueira and Crowder 2006). California sea lions (Zalophus californianus) in the Gulf of California (GoC) are thought to include distinct populations based on limited dispersal and resulting genetic population structure (Schramm-Urrutia 2002). Comparisons of mitochondrial DNA collected from pups located on seven GoC rookeries suggest three distinct populations occur within the GoC (Schramm-Urrutia 2002). Although marked 1-yr-old juveniles have been identified on islands far from their natal site (>600 km), these occurrences are uncommon (Hernandez-Camacho 2001). Here, we report a neonate (i.e., a newbornold) sea lion traveling >600 km during an 18-d period. Our observation represents the first published report of long-distance neonate movement among pinnipeds.