Avid divers, there are now two Marine Park Dive Trails on Sisters' Islands. The two trails opened Nov 8, and each one is 100m in length.
The shallower trail is about five to six meters deep, and leads to the more advanced deep trail, which lets divers plunge to a depth of 15m. You may see some feather duster worms (ew or cool?), giant clams, anemone and clownfish. There are 20 stops along the way with signs highlighting what creatures can be found there.
If you're a new diver, you'll have to log in more dives because an advanced level of certification is required. You also have to have good buoyancy control, and be able to deal with rough currents and low visibility.
Check out the official website that will inform you of future dive dates. Register for the next dive on Nov 22 with either GS Diving or Opcon Diving, as stated on the NParks website. Prices vary depending on the operator.
Not experienced enough yet? Get some inspiration at the Sisters' Island Facebook page where there are lots of images of the creatures you can expect to find at the dive trails.
He will love it.