The cache is a black plastic toolbox screwed to a Pohutukawa tree branch about 10m above the rocky shore. It's a scramble up the hill, use the saplings for grip. The tree is directly up from a large horizontal rock, black with orange lichen. There are a couple of similar rocks, so we have cable-tied four successive orange plastic markers to saplings, visible from the rock upwards.
As you can see from visitor's comments, this little bay is well worth the effort. It's a sheltered little paradise for kids to get snorkelling practice with a sandy bottom and a few seaweed rocks. Boats can anchor in the bay for a swim to the island, and kayaks can be pulled onto the boulders. We find the best spot to land kayaks is in the sandy right hand corner (as you look at the bay from the sea). We hop off our kayaks waist deep over the sand and hand-float them to pull up on the rocks there.
Mahurangi Island forms one boundary of the Hahei Marine Reserve which extends across to Cathedral Cove. To see big schools of blue mao mao, baby snapper and red moki, drop in for a snorkel at the front of Okorotere Island (the little island off the north-west end of Mahurangi Island.
The toolbox and everything it contains was bought from Pinky's next to the movie theatre in Whitianga: logbook, pencil, sharpener, eraser, and a random object. By all means take the object and leave another one!
Be gentle, and be prepared! last time we looked this geocache box had become the residence of a family of native geckos, which kinda leapt out as the lid was opened :)