Harbor seals (Phoca vitulina) are more solitary than many other pinnipeds. Yet, they are capable of vocal learning, a form of social learning. Most extant literature examines social animals when investigating social learning, despite sociality not being a prerequisite. Here, we report two formerly silent harbor seals who initiated vocalizations, after having repeatedly observed a conspecific receiving food rewards for vocalizing. Our observations suggest both social and vocal learning in a group of captive harbor seals, a species that lives semi-solitarily in the wild. We propose that, in this case, social learning acted as a shortcut to acquiring food rewards compared to the comparatively costly asocial learning.