Diving and snorkeling:
Tofo and surrounds have some truly excellent diving, with beautiful reefs and excellent large marine life. Most of the better dive sites are at around 25-30m, requiring deep-dive certification (which you can get through one of the dive shops if you don't have it already). Visibility is usually pretty good at around 20m.
Tofinio is a good surf spot, and Tofo beach is good for beginners, snorkelling is a must….
All within walking distance.