Fireworks sound is widely recognized to negatively affect domestic animals, yet their impacts on wild taxa remain poorly documented. Evidence from terrestrial and marine bird species indicates acute behavioral changes in response to fireworks and, in some cases, longer-term population impacts. Fewer studies have focused on marine mammals, with some evidence of temporary displacement of seals from their regular haul-out sites. In South Africa, the Victoria and Alfred Waterfront provided an opportunity to study fireworks sound impacts on semi-habituated marine species during the New Year’s Eve (NYE) celebration over 2 years. A short-term study conducted over the 2023 NYE fireworks display period demonstrated acute behavioral responses of seals and gulls to the fireworks, prompting a more detailed study over a longer 6-week period spanning the 2024 NYE celebration. These observations indicated acute short-term displacement of marine mammals but no measurable long-term impacts. Furthermore, there was little underwater anthropogenic sound impact, with sounds from harbor-related activities dominating the underwater soundscape. As the ocean is a refuge for amphibious species, collective research suggests that fireworks are more impactful to species that live predominantly on land, for example, birds, where there is evidence of long-term reproductive implications.