The ministers have been receiving training at a military base
The government of the Maldives is to hold a cabinet meeting underwater to highlight the threat of global warming.
President Mohamed Nasheed and his cabinet will sign a document during the 17 October dive, calling for global cuts in carbon emissions.
An adviser to the president told the BBC the dive was "a bit of fun" but the cabinet intended to send a serious message about rising sea levels.
The low-lying island nation says it faces being wiped out if oceans rise.
The adviser, who asked not to be named, said ministers would communicate during the meeting using hand signals and waterproof boards and pens.
The cabinet will be joined by instructors and military escorts
"Obviously the hand signals that divers can use are limited, so the amount of work the cabinet are going to get done will be limited," he said.
"But they will call on all nations - rich and poor, developed and developing - to take climate change seriously."
All cabinet members bar one - who has a medical condition that rules out diving - have been in training at a military base on one of the country's many islands.
Mr Nasheed, who is already a qualified diver, will also hold a press conference in the water.
While underwater, the government will sign a document ahead of the UN Climate Change Conference in Copenhagen in December, calling on all nations to cut down their carbon emissions.
World leaders at the summit are aiming to create a new agreement to replace the 1997 Kyoto Protocol, which expires in 2012.
The dive is being held to mark the 350 International Day of Climate Change Action on 24 October.
The Maldives is the world's lowest-lying country
The day's organisers say they want to highlight the risks of rising carbon in the atmosphere and encourage world leaders to commit to reducing carbon dioxide levels in the atmosphere to 350 parts per million.
That is the amount some scientists say is the safe upper limit to avoid irreparable damage to the environment.
Some 80% of the Maldives archipelago is less than a metre above sea level and is extremely vulnerable to any rise in sea levels as a result of global warming melting the polar ice caps.
Officials say that by the time the Maldives feels the full effect of climate change, it will be too late to save other countries.
Mr Nasheed has warned that the entire nation may have to find a new home if the oceans rise as predicted by the UN.
The president's adviser told the BBC that although the country's government was almost all going to be underwater at the same time, there was no real danger.
Each minister will be accompanied by a diving instructor and a military minder and the local sharks were "friendly", he said.