A South Korean shipbuilder said Wednesday it had signed the country's largest-ever weapons export deal, worth $1.1 billion, to sell three submarines to Indonesia.

It also marked the first time that South Korea has grabbed a deal to sell submarines abroad, Daewoo Shipbuilding and Marine Engineering said in a press statement.

Under the contract, Daewoo will deliver the three submarines, each weighing 1,400 tons, to Jakarta by the first half of 2018.

Each of the submarines can carry 40 personnel and will be equipped with eight weapons tubes to fire torpedoes and guided missiles.

The deal brings the volume of South Korea's defence exports this year to an all-time record $2.4 billion, more than double the amount from a year ago, the state-run Defense Acquisition Program Administration (DAPA) said.

It is the second major defense deal between the two countries. In May, the South's state-run Korea Aerospace Industries (KAI) agreed to export 16 supersonic T-50 Golden Eagle trainer jets worth $400 million to Jakarta.