"If global warming continues as predicted, 600 of these islands will disappear and many of those that remain will be uninhabitable. This is why they are making this publicity statement", Cole said.
Ministers used white boards to communicate under water.
"But the real message they want to communicate is that the world must reduce emmissions or else the nation will disappear", Cole noted.
Sitting round a horseshoe-shaped table, all but three of the 14-member cabinet took part in the meeting.
The Divers Association of Maldives (DAM) said the ministers trained over the past two months for the dive.
Event organisers said the ministers had signed their wetsuits and would be auctioning them on the protectmaldives.com website to raise money for coral reef protection in the atoll-chain.
The Maldives, located southwest of Sri Lanka, has become a vocal campaigner in the battle to halt rising sea levels.
In 2007, the UN's Intergovernmental Panel on Climate Change warned that a rise in sea levels of 18 to 59 centimetres by 2100 would be enough to make the country virtually uninhabitable.
More than 80 per cent of the country's land, composed of coral islands scattered some 850km across the equator, is less than one metre above sea level.