The deal between the Turkish arms procurement agency and Germany's ThyssenKrupp Marine Systems for the joint manufacture of six submarines has formally taken effect.
The German group stated, "The €2bn order for six U214 submarine material packages placed with ThyssenKrupp Marine Systems by the Republic of Turkey has entered into force with receipt of the advance payment."
The original submarine contract worth €2.5bn was signed between Turkey and HDW, an affiliate of the ThyssenKrupp conglomerate, in July 2009, however, renegotiations over price led to a price reduction of more than €500m.
The U214 submarines will enter service shortly after 2015, two years later than the original schedule.
Turkey is also building its own corvette-type ships and hopes to produce its own frigates by the end of this decade.