Finland’s incoming F-35A Lightning II fighters will lack several capabilities outlined in the original procurement agreement, requiring the Finnish Air Force to fund major post-delivery upgrades. Henrik Elo, head of Finland’s F-35 program, disclosed this to Helsingin Sanomat on April 9, 2026.
The shortfall traces to ongoing delays in the F-35 Block 4 upgrade, which modernizes software, sensors, and weapons systems. A September 2025 US Government Accountability Office report projected completion no earlier than 2031, a five-year delay from initial plans, with the scope reduced from over 75 capabilities.[1] All 110 F-35s Lockheed Martin delivered in 2024 arrived late by an average of 238 days, mainly due to Technology Refresh 3 integration problems.[1]
Elo stated that Finland’s 64 aircraft, built in TR-3 configuration and valued at about 10 billion euros including weapons and support, will receive upgrade packages as they become available. Some will occur before full operational capability in 2030, but final retrofits, covering software and hardware, may extend past the mid-2030s. No compensation comes from Lockheed Martin, leaving Helsinki to cover costs from project and maintenance budgets.
Engine upgrades add complexity. Block 4 demands more power and cooling than the current Pratt & Whitney F135 provides, necessitating an engine core upgrade not entering production before 2031 and possibly delaying some features to 2033.[1] Finland thus anticipates overlapping modernizations after 2030: Block 4 retrofits and full engine replacements.
This pattern affects other operators. Switzerland trimmed its order from 36 to about 30 aircraft in March 2026 amid rising costs.[1] Block 4 expenses have ballooned from $10.6 billion to $16.5 billion as of 2021, plus $6 billion in overruns.[1]
Finland’s first F-35A, JF-501, rolled out in December 2025 and reached Ebbing Air National Guard Base in Arkansas for training. Deliveries to Rovaniemi in Lapland start in 2026, replacing F/A-18C/D Hornets phased out by 2030.