PUBLISHED on August 8, 2025, 09:56 AM EDT – Key Points and Summary – New concept renderings from Korea Aerospace Industries (KAI) have revealed major planned upgrades for South Korea’s KF-21 fighter, known as the KF-21EX.
-The images show significant stealth enhancements, including the addition of internal weapons bays, a redesigned canopy, and a new F-35-like electro-optical targeting system.
-These upgrades, which aim to push the 4.5-generation jet into a true fifth-generation classification, are being unveiled even before the base model of the domestically developed fighter enters service in 2026.
-This signals South Korea’s ambition to counter growing regional threats.
Renderings Reveal New Tech Coming to South Korea’s KF-21EX
New concept artwork released by Korea Aerospace Industries (KAI) reveals more details about a planned upgraded version of the KF-21 Boromae fighter, the KF-21EX.
The new images, a series of digital renderings, offer insight into plans to make the Block 1 South Korean Boromae multirole fighter more survivable amid rapidly advancing air defense systems.
What the New Images Show
The new images confirm a wide range of new technologies and features in the works for the KF-21EX, ranging from sensor and avionic upgrades to stealth and survivability enhancements.
New electronic and situational awareness systems are also anticipated for the jet, along with multiple physical and structural changes.
The renders depict twin internal weapons bays – a feature not currently present on the Block 1 design. The proposed aircraft is depicted carrying what appear to be two 2,000-pound-class guided bombs.
A new sensor is also fitted below the nose, which is expected to function in a similar manner to the Electro-Optical-Targeting System (EOTS), a system already found on the American F-35 that is designed to track and locate targets during aerial warfare.
In terms of stealth, a reprofiled canopy and redesigned radome are designed to reduce radar cross-section and improve the overall stealth profile of the aircraft. The aforementioned internal weapons carriage seen in the renderings would also serve to improve stealth. KAI also hinted, as part of the release, at additional experimental systems being considered to enhance survivability.
Upgrades Emerge Before Block 1 Production
The KF-21 Boromae is South Korea’s first domestically-developed advanced multirole fighter, designed to reduce dependence on foreign platforms and improve South Korea’s defense capabilities as the country faces growing threats from North Korea, uncertainty around long-term U.S. security guarantees, and rapid Chinese aerospace advancements.
Developed by Korea Aerospace Industries with support from Indonesia, the aircraft is a 4.5-generation fighter that may soon – thanks to planned upgrades – finally be reclassified as the fifth-generation fighter it was initially envisioned to be. Some have even called it a ‘Mini’ F-35 stealth fighter.
Notably, the KF-21 is not yet in operational service. The aircraft’s first flight took place in July 2022, and the Block 1 variant is expected to be formally introduced in 2026. The KF-21 will be capable of speeds up to 2,200 kilometers per hour, with a range of 2,900 kilometers.
With over 1,000 test sorties logged so far, the program is moving steadily toward production – and as geopolitical tensions rise across Northeast Asia, fueled in part by North Korean drone, missile, and tactical nuclear weapons development, the KF-21 and its upgraded EX variant could give South Korea a cost-effective solution designed entirely with its own needs in mind.
About the Author:
Jack Buckby is a British author, counter-extremism researcher, and journalist based in New York. Reporting on the U.K., Europe, and the U.S., he works to analyze and understand left-wing and right-wing radicalization, and reports on Western governments’ approaches to the pressing issues of today. His books and research papers explore these themes and propose pragmatic solutions to our increasingly polarized society. His latest book is The Truth Teller: RFK Jr. and the Case for a Post-Partisan Presidency.
More Military
America Almost Had to Invade Japan