KF-21 Boramae: the Korean jet the Philippines is weighing
What the KF-21 Boramae is, why the Philippines is weighing South Korea's new fighter, what is and isn't agreed, and what a fighter fleet really costs to run.
Why it matters
The Philippines is choosing jets that will guard its seas and airspace for decades, on a modernization budget of about 40 billion pesos ($691 million) a year. How it pays to buy and run them matters as much as which jet it picks.
The KF-21 Boramae, South Korea’s first home-built fighter jet, joined its air force on September 22, 2026. The Philippines is now weighing whether to buy it, but no deal has been signed and Manila has not confirmed how many jets it wants, or even which type.
Quick answer: The KF-21 Boramae is a twin-engine, 4.5-generation fighter built by Korea Aerospace Industries (KAI). Philippine defense officials are studying it as one of several candidates for a new multirole fighter fleet. Reported Korean offers cover 12 to 20 jets. The often-quoted figure of 40 is the Philippine Air Force’s total fighter goal, not an order.
The interest makes sense on paper. The Philippine Air Force already flies KAI’s smaller FA-50 jets, it is short of money, and it wants aircraft that can patrol a long maritime border facing China. But the Boramae is new, its ground-attack and anti-ship weapons are still being developed, and the price on the brochure is only a small part of what a fighter costs over 30 or more years.
What is the KF-21 Boramae?
The jet was designed to replace South Korea’s aging F-4 and F-5 fighters, with KAI as the prime contractor.
It is usually called a 4.5-generation fighter. That puts it a step above jets such as the F-16 in design, with a shape that cuts its radar signature, but short of a true stealth aircraft like the American F-35. The main reason is weapons carriage: early versions hang missiles outside the airframe, partly recessed under the belly, instead of hiding them in an internal bay.
The basic figures, as reported by KAI and defense publications:
| Feature | KF-21 Boramae (Block I) |
|---|---|
| Builder | Korea Aerospace Industries (KAI) |
| Engines | Two General Electric F414 turbofans |
| Top speed | About Mach 1.8 (roughly 2,200 km/h) |
| Range | About 2,900 km (ferry) |
| Weapons load | Up to 7,700 kg on 10 hardpoints |
| Radar | Korean-made AESA (Hanwha Systems) |
| Estimated price | About $65 million to $90 million per jet, before weapons and support |
Source: KED Global, October 18, 2024; Defence Security Asia, September 2026.
About 65% of the jet’s value is Korean-made, according to Defence Security Asia. The engines, ejection seats and some avionics are imported, so other governments can have a say in export deals and in which weapons a buyer gets.
Block I, Block II: what the jet can do today
South Korea is buying the KF-21 in stages, called blocks. The air force plans 40 Block I jets by 2028 and 80 Block II jets by 2032, for about 120 in total, The Aviationist and Defence Security Asia report.
Block I is mainly an air-to-air fighter. When KED Global reported on the Philippine competition in 2024, the jet was air-to-air only, and KAI planned to add air-to-ground capability with an upgraded production version by 2028. Block II is the version meant to bring precision strike and maritime attack, including guided bombs and, later, cruise and anti-ship missiles. That work is still under way.
For the Philippines, this is the most important detail in the whole debate. A jet ordered now and delivered in the late 2020s would likely start life as an interceptor and air-patrol aircraft. Its ability to hit ships or targets on land would depend on Block II upgrades, weapons integration and export approvals arriving on time.
A later Block III, sometimes called KF-21EX, is meant to add internal weapons bays and more stealth treatment. It is a long-term plan, with a first flight of a new Korean engine targeted for 2040, according to The Aviationist.
How the Boramae got here
The program, first known as KF-X, took more than a decade from the start of development to the first delivery.
- 2015: Development begins, with Indonesia as a partner paying 20% of costs.
- April 2021: The first prototype is unveiled.
- July 2022: The prototype makes its first flight.
- May 2024: Indonesia proposes paying about a third of its agreed share, Reuters reports.
- Mid-2024: Serial production starts.
- January 2026: Developmental flight testing ends, after six prototypes flew without a crash.
- April 15, 2026: The first production jet flies.
- September 22, 2026: The first production KF-21 is delivered to the Republic of Korea Air Force’s 156th Fighter Squadron at Yecheon.
Indonesia’s troubled partnership
Indonesia was meant to be the program’s foreign anchor. It agreed to pay part of the development bill in return for technology, prototypes and the right to build jets at home.
The money did not arrive on schedule. Indonesia fell behind on payments from 2017, Defense News reported. In May 2024, Reuters reported, citing Korea’s Yonhap news agency, that Indonesia offered to pay about 600 billion won (about $440 million) instead of roughly 1.6 trillion won owed by June 2026, and to accept less technology in return. South Korea agreed to the cut later that year.
The relationship has shifted again in 2026. Meta-Defense and Janes reported a January 7 meeting in Indonesia on Korean export-bank financing for 16 Block II jets. In late June, Indonesian reports said the defense ministry would drop plans to co-produce the jet and would buy it directly instead. The Aviationist describes Indonesia’s role as reduced amid disputes over funding, work share and alleged industrial espionage.
For Manila, the lesson is mixed. The program survived a partner that fell years behind on payments. It also shows how hard it is to keep a fighter deal on track when a buyer’s budget is tight.
Why is the Philippines looking at the KF-21?
The Philippine Air Force launched its multirole fighter project in August 2024, KED Global reported, as China’s presence in the South China Sea grew. The plan sits inside the military’s modernization program, now in its third phase, known as Re-Horizon 3. The defense department says new jets fit its Comprehensive Archipelagic Defense Concept, a strategy built around guarding the country’s islands, seas and airspace.
The target is about 40 multirole fighters, according to Defense News and KED Global. That is the air force’s goal for the whole program. Korean proposals discussed between June and August 2026 covered 12 to 20 KF-21s, Defence Security Asia and Meta-Defense report, with possible Korean concessional loans, a maintenance center at Clark and deliveries between 2027 and 2029.
The KF-21 is not the only candidate. In July 2026, Defense Secretary Gilberto Teodoro Jr. still listed five: the KF-21, Lockheed Martin’s F-16, Saab’s Gripen, Dassault’s Rafale and the Eurofighter Typhoon, according to Defence Security Asia. Defense News reported in February that the Gripen, Typhoon and KF-21 had all been pitched.
Some outlets have reported that Manila is “leaning” toward a single fleet of 40 Boramae jets. Defence Security Asia, which reported that view, describes it as an analyst assessment and says neither the government nor the air force has confirmed the number, the type or a timetable. A decision has been projected for between late 2026 and mid-2027.
The FA-50 connection
The Philippines is already one of KAI’s best customers. It bought 12 FA-50PH light fighters for 18.9 billion pesos, a deal signed in 2014, with deliveries from 2015. They were meant partly as a bridge, training pilots for more advanced jets later.
In June 2025, the defense department bought 12 more, the improved FA-50 Block 70, in a deal worth more than $700 million, with deliveries due to finish by 2030.
That history is KAI’s strongest sales point. Pilots, mechanics and spare-parts systems already work with Korean jets, which Meta-Defense says could ease the arrival of a bigger one. KAI has floated a mix of at least 40 FA-50s and 20 KF-21s, Defence Security Asia reports, and the company has said a large maintenance base only pays off with enough aircraft to service.
What happened to the F-16 offer?
On April 1, 2025, the U.S. State Department approved a possible sale of 20 F-16 Block 70/72 jets to the Philippines, with an estimated value of $5.58 billion, the Defense Security Cooperation Agency announced. The figure is an estimated ceiling for the whole package, not the price of the aircraft alone.
Teodoro sent Lockheed’s proposal back. “It was beyond the approved budget ceiling,” he said, according to Defense News. He has argued that funding, not the choice of jet, is the real constraint, and the U.S. deal has been described as on hold rather than dead.
| Option | Reported figure | Status |
|---|---|---|
| F-16 Block 70/72 (US) | $5.58 billion for 20 jets with support | Approved by Washington April 2025; returned as over budget |
| KF-21 Boramae (South Korea) | About $1 billion to $1.93 billion for 12 to 20 jets (reported) | Proposals discussed mid-2026; no contract |
| Gripen, Rafale, Typhoon | No public Philippine price | Still listed as candidates in July 2026 |
Source: Defense Security Cooperation Agency, April 1, 2025; Defense News, February 13, 2026; Defence Security Asia, September 2026.
The two numbers are not a fair comparison. The American figure is a ceiling for a full package, and the Korean figures are reported offers whose contents have not been published.
What a fighter really costs over its life
The sticker price is the smallest part of owning a fighter fleet. Fuel, spare parts, engine overhauls, pilot training, simulators, munitions and software updates add up every year for three decades or more.
The clearest public numbers come from the U.S. Government Accountability Office’s work on the F-35. In an April 2024 report, the GAO put the cost to operate and sustain the U.S. fleet at $1.58 trillion, out of more than $2 trillion to buy and run it through 2088. The U.S. Air Force expected to spend about $6.6 million a year to keep each jet flying, against an original target of $4.1 million.
The F-35 is a costlier jet than the KF-21, but the pattern holds for most fighters: the bill keeps arriving long after the purchase. That is why Teodoro has pushed for a “full package” of fighters with early-warning aircraft and tankers, according to Defence Security Asia, and said jets should not end up “sitting on a ramp.”
The Philippine budget makes this hard. The 2026 defense budget rose 12.3% to 310 billion pesos ($5.35 billion), Defense News reported, but modernization money stayed flat at 40 billion pesos ($691 million) a year. Teodoro told lawmakers to “stop kidding around” with that figure and floated longer-term loans and project-based funding. At that level, a $1 billion jet deal would cost more than a full year of the entire modernization budget unless it comes with loans.
That is where the Korean pitch is strongest. Cheaper jets, concessional financing and a local maintenance base all lower the yearly cost. The trade-offs are an aircraft with no combat record, strike weapons that are still in development, and some American-made parts that keep Washington involved anyway.
How to read the next headlines
Most of what has been reported so far comes from Korean industry sources and defense trade publications, not from Manila. Treat numbers carefully until the Philippine government confirms them.
Watch for: a notice of award or signed contract from the Department of National Defense; whether the deal names 12, 20 or 40 jets; whether it includes Block II strike capability and which missiles come with it; the financing terms, especially any Korean export-bank loan; and whether Congress funds modernization above 40 billion pesos in the 2027 budget.
A contract that lists the jets, the weapons, training and the first five years of support will tell you far more about the deal than its headline price.
