Mercury Bay is the name on the map, and Whitianga is the town that wraps around it, on the eastern side of the Coromandel Peninsula where the Pacific comes in flat and blue and rather unhurried. Captain Cook anchored here in November 1769 to watch the transit of Mercury, which is how the bay got its name, and Māori ancestors had been using the harbour long before that. The beach in front of the town is a long, gentle curve of pale sand with shallow water, the sort of beach where you can leave your jacket and boots on a bag and actually swim without negotiating surf.
You get here on State Highway 25, which on this peninsula is a road with opinions. From Thames it crawls up the Firth of Thames shore under old pōhutukawa trees, then cuts across the ranges, climbing through bush with tight, damp bends where the surface changes colour with every patch of shade. Gravel on the apexes is a regular feature after rain, and it rains with enthusiasm on the Coromandel.
Whitianga itself is easy. With a population of a little over three thousand it has fuel in town, cafes along the waterfront, and a small passenger ferry that crosses to Ferry Landing on the Kuaotunu side if you feel like a pointless but charming minute on the water. Coromandel town, about twenty kilometres up the coast, is the next real stop for supplies, and Tairua is a similar hop south. Thames, thirty-odd kilometres back, is the larger town with the bigger supermarkets and mechanics if something needs attention.
The reason to linger is the coast itself. A short drive from town you get Cathedral Cove and Hot Water Beach, where at low tide people dig their own spa pits in the sand above a geothermal spring, and both are busy in summer and almost empty in winter. Scallops are a local pride, and the fish and chip shops tend to be worth their reputation. Come between late spring and early autumn if you want warm water, but I like the shoulder months, when the light is low and golden over the bay and you can park the bike with nobody to apologise to.