Nelson Haven is an estuary with coastal salt marsh and mudflats, northeast of Nelson, New Zealand.^[1] It is separated from Tasman Bay / Te Tai-o-Aorere by the Boulder Bank.^[1] It is over 8 km long and up to 2 km wide. The area is regularly completely drowned and exposed by tidal action and supports a large population of mud crabs.

41°14′24″S 173°18′18″E / 41.24000°S 173.30500°E / -41.24000; 173.30500