Bournda Lagoon has formed behind Bournda Beach, between Tathra and Merimbula in Bournda National Park. The lagoon is deep enough for swimming and is a popular spot for a freshwater swim. The lagoon is fed by Sandy Beach Creek, which has been silted up at the southernmost end of Bournda Beach. The lagoon supports a variety of environments, including a rainforest, on its shores. However, the lagoon is subject to environmental issues such as algal blooms. The lagoon can be accessed by bush track from Bournda Lagoon car park, at the end of Bournda Rd.