Cloudy Bay is located at the northeast of New Zealand's South Island, to the south of the Marlborough Sounds. A recent Waitangi Tribunal settlement will see Cloudy Bay, given this name by Captain Cook in 1770, renamed Te Koko-o-Kupe / Cloudy Bay, with the Māori name recalling the early explorer Kupe scooping up oysters from the bay

The area lends its name to one of the best known New World white wines (Cloudy Bay Vineyards Sauvignon Blanc) although the grapes used in production of that wine are grown in the Marlborough wine region further inland.

The bay faces Cook Strait, stretching north-south over a distance of 30 kilometres from the southern extremity of the Marlborough Sounds (Port Underwood) to White Bluffs. Along its length is the delta of the Wairau River, which reaches the sea at two points. The southern of these forms an entrance to the Big Lagoon, just to the north of White Bluffs.