Nelson Commonwealth Marine Reserve is a 6,123 km2 marine protected area within Australian waters located in the Southern Ocean[2] near the South Australia-Victoria border.

The reserve was established in 2007[3] and is part of the South-east Commonwealth Marine Reserve Network.

The reserve spans deepwater ecosystems (below 3,000 m (9,800 ft)) and encloses geological features including plateaus, knolls, canyons and the abyssal plain.

It is an important migration area for humpback, blue, fin and possibly sei whales.

[4] The entirety of the Nelson marine reserve area is IUCN protected area category VI and is zoned as 'Special Purpose'.