Double Bay is a freedom camping reserve situated on Moetapu Bay Road within Mahau Sound, part of the Marlborough Sounds region of New Zealand's South Island.

The site offers grassy camping areas with panoramic views over the water and is managed by the Marlborough District Council. Camping is restricted to certified self-contained vehicles only, with a maximum of six vehicles permitted at any one time.

Stays are limited to two consecutive nights within any four-week period. No bookings are required — it operates on a first-come, first-served basis.

Campers must be fully self-contained, as there are no public toilet facilities on site; all rubbish must be carried out.