If you're heading to Rangitoto Island, Boulder Bay is a great spot to also check out, you'll most likely not come across anyone else. Boulder Bay is also know as 'Wreck Bay' due to the area being a dumping ground for old ships. Great place to explore and even snorkel if you're up for it! (Low tide is best)
From the Fullers site:
'If you keep walking a further hour along a winding path from Islington Bay, you’ll come to Wreck Bay and its adjacent Boulder Bay. These bays aren’t as good as the other two for swimming, but they are of great heritage significance, as they were once a dumping ground for old ships. Best explored at low tide when some of the ships can be seen from the shore.'
From a reviewer:
'Also known as Wreck Bay, there a is beautiful track, very well defined, that connects Boulder bay with the road that goes from Islington Bay to the Rangitoto crater.
You can see very old rusty wreckage from several ships, specially when the tides are low.'