Sayyari takes over the position from Rear Admiral Sajjad Kouchaki.
Kouchaki, who became navy commander in September 2005, was previously deputy head of planning and budget of Irans armed forces.
Iran has a dual military system with a regular armed forces as well as the Islamic Revolutionary Guards Corps (IRGC). Both have their own army, navy, and air force and report directly to Supreme Leader Khamenei.