The submarines are equipped with eight 533-millimeter bow-mounted torpedo tubes and can stay up to 50 days at sea.
Neighboring Singapore and Malaysia as well as the United States and Australia were among the nations who helped in the hunt for the submarine, with nearly two dozen warships deployed to scour a search zone covering about 10 square nautical miles.
Riad confirmed that the submarine lost contact when it was 60 miles away from Bali Island on Wednesday April 21.