After months of speculation, Iran has confirmed the acquisition from Russia of  24 Su-35 (NATO reporting name: Flanker-E) multirole fighters. The jets would arrive in the coming Iranian year, which begins on March 21. The SU-35 is one of the most advanced planes in Russian service, second only to the SU-57, a 5th-generation stealth plane equivalent to the United States F-22 Raptor. Military cooperation between Iran and Russia is not new, dating back to Cold War times. Russia has supplied  advanced military hardware to Tehran, such as the air defence system S-300. But the particularity of the SU-35 deal is that it was preceded by a reversal of roles, with Iran supplying military equipment to Russia. The Iranian-made Shahed -136/131 drones have been a crucial element of Russia’s strategy to terrorise Ukraine’s population and strike civilian infrastructure. This two-way street military cooperation is a sign of the deepening of the strategic alliance between Moscow and Tehran.

Iran has been successful in developing a domestic drone and missile industry; however, the Achilles' heel of Iranian defence is its air force. The Islamic Republic of Iran Air Force (IRIAF) inventory includes some museum pieces of the United States aviation history, a legacy from the times of the Shah, when Iran was a major ally of Washington. The core of IRIAF's fighter fleet is composed of vintage aircraft like the F-4 Phantom II, a Vietnam War symbol. Iran's air force has the distinction of being the only foreign user of the US Navy fighter F-14 Tomcat. IRIAF operates other fighters like the French Mirage F-1 and Russian Mig-29. IRIAF inventory is diverse in aircraft models and origin. However, a common denominator is the old age of its airframes, causing frequent crashings that have killed several pilots.

The obsolescence of most IRIAF planes puts Iranian air power far behind its regional rivals, Saudi Arabia and Israel, both of which have modern Western aircraft. The SU-35 is a capable fighter that could level the field against Saudi's Eurofighter and F-15. Still, the SU-35 would be at a disadvantage in long-range combat against a stealth aircraft like the F-35, the Israeli Air Force weapon of choice for an attack against Iran's nuclear facilities. However, due to its speed and manoeuvrability, the Russian jet would have the upper hand in a close combat scenario. Even less technologically advanced than the F-35, the Flanker E represents the best option in the Iranian aircraft inventory for repelling an attack on its nuclear installations.

Whether the SU-35 will be a game changer for Iranian air power will depend on many factors, such as how quickly Iranian pilots can master the Flanker's complex avionics or if Russia can guarantee supplies for spare parts. But at least on paper, the SU-35 is a significant upgrade for Iran's aerial capabilities.