Where to buy fins on Oahu?

You can buy fins on Oahu at several locations, including local surf shops like Hawaiian South Shore and Surf N Sea, which offer a variety of options for different water activities. Additionally, larger retail stores such as Walmart and Costco may have fins in their sporting goods sections. For a wider selection, you can also check online retailers or visit specialty dive shops. If you're looking for second-hand options, consider checking out local classified ads or Facebook Marketplace.