The U.S. Navy has successfully completed the third and final planned flight test of the Harpoon Block II Update (HIIU) Obsolescence Update program, marking a major milestone in sustaining one of the world’s most widely deployed anti-ship missile systems while extending its relevance for modern, multi-domain warfare.
The Naval Air Systems Command (NAVAIR) announced that the test was conducted on January 16, 2026, at Naval Air Weapons Station China Lake and across the Point Mugu Sea Range in California. The event was carried out by the Precision Strike Weapons (PMA-201) program office in close coordination with Boeing and other industry partners.
For the final test flight, the U.S. Navy employed one of Boeing’s instrumented F-15SA aircraft to launch the AGM-84 Harpoon Block II Update over the Point Mugu Sea Range. The successful demonstration confirmed the missile’s ability to execute a complex coastal strike mission against a representative land-based target, completing the three-event test series designed to validate the HIIU across its full operational envelope.
Notably, the aircraft used in the final test was F-15 12-1002, one of three highly instrumented F-15SA (Saudi Advanced) aircraft operated by Boeing from its Palmdale, California facilities. While the F-15SA is primarily flown by the Royal Saudi Air Force, these instrumented jets are routinely used by Boeing and U.S. defense organizations for weapons integration, flight testing, and certification activities.
The F-15SA holds a unique position within the Eagle family. Alongside South Korea’s F-15K Slam Eagle, it is one of only two F-15 variants cleared to employ the AGM-84 Harpoon anti-ship missile and its land-attack derivative, the AGM-84H/K Standoff Land Attack Missile-Extended Range (SLAM-ER). This made the Saudi-configured F-15SA an ideal platform for the Navy’s final HIIU test event.
Although the U.S. Air Force does not operate Harpoon or SLAM-ER on its F-15E Strike Eagle fleet, the aircraft’s size, payload capacity, and advanced avionics make it a valuable surrogate test platform for demonstrating air-launched maritime and coastal strike capabilities.
According to NAVAIR, the January 16 test “demonstrated a successful Coastal Target Suppression mission against a representative land target, with all test objectives met based on preliminary assessments.”
During the event, the Harpoon Block II Update was released from the F-15 at approximately 12,000 feet above ground level. Following launch, the missile descended to an initial waypoint altitude of around 5,000 feet before proceeding toward the target area. Throughout the flight, the weapon executed multiple altitude changes designed to simulate a realistic coastal engagement profile, before performing a steep terminal dive just prior to impact.
This flight profile highlights the evolution of the Harpoon from a pure sea-skimming anti-ship missile into a more flexible strike weapon capable of navigating complex littoral environments. While the original Harpoon was optimized to detect and engage surface combatants using its active radar seeker, the Block II configuration added a GPS-aided navigation system that enables attacks against fixed land targets in coastal regions.
The ability to pre-program multiple waypoints allows the missile to avoid known threat areas, terrain features, or friendly forces, while still retaining its radar seeker for terminal guidance when required.
The land-attack capability of the Harpoon was first demonstrated more than two decades ago. In 2001, Boeing conducted initial tests showing that a modified Harpoon Block II could strike coastal land targets with high accuracy using GPS guidance.
To achieve this, Boeing incorporated a low-cost inertial measurement unit derived from the Joint Direct Attack Munition (JDAM) program, along with software, mission computer elements, an integrated GPS/Inertial Navigation System, and a GPS antenna borrowed from the SLAM-ER. By coupling GPS/INS guidance with the existing active radar seeker, the missile gained the ability to navigate precisely to a target search area, even in environments where radar-only guidance might be degraded.
The seeker can be instructed to search specific areas while avoiding others, increasing survivability and reducing the risk of collateral damage in cluttered coastal zones.
HIIU: A Near-Total Internal Redesign
While the Harpoon Block II’s operational concept is well established, the Harpoon Block II Update Obsolescence Update represents a significant internal modernization rather than a simple software refresh.
NAVAIR has described the HIIU as a near-total redesign of the missile’s internal components, replacing aging electronics and subsystems that were becoming increasingly difficult to sustain due to obsolescence. Many of the original Harpoon components date back decades, creating supply chain challenges and driving up maintenance costs.
Testing of the HIIU variant began in 2025 and was structured around three progressively complex flight events. The first test, conducted in mid-2025, focused on validating basic guidance and aerodynamic performance following the internal redesign. The second event demonstrated the missile’s ability to engage a moving maritime surface target, confirming that the updated electronics did not degrade the Harpoon’s core anti-ship role.
The third and final test, completed in January 2026, confirmed effectiveness against a land-based target, completing the full mission set envisioned for the HIIU.
According to NAVAIR, system-level flight testing for the Harpoon Block II Update Obsolescence Update is now nearly complete, with initial deliveries to the fleet planned for later this year.
Program Leadership Highlights Industry-Government Teamwork
“This milestone reflects the strength of the integrated government and industry team and their commitment to delivering reliable, relevant capability to the fleet,” said Capt. Sarah Abbott, PMA-201 program manager.
Her remarks underscore the Navy’s broader approach to weapons modernization: extending the service life and operational relevance of proven systems while balancing cost, risk, and the need to field advanced capabilities quickly.
For many allied and partner nations, Harpoon remains a cornerstone of maritime strike doctrine, deployed from ships, submarines, and aircraft. Ensuring that the missile remains supportable and effective well into the future is therefore not only a U.S. Navy priority, but also a key concern for numerous foreign operators.
The involvement of the F-15 in the HIIU test also highlights a lesser-known aspect of the Eagle’s evolution. Originally designed as a pure air superiority fighter, the F-15 later expanded into the multirole domain with the F-15E Strike Eagle and its derivatives.
While the Strike Eagle family is best known for deep strike, close air support, and interdiction missions, certain export variants have carved out a niche in the maritime strike role.
At present, only the Royal Saudi Air Force’s F-15SA fleet and the Republic of Korea Air Force’s F-15K fleet routinely employ anti-ship weapons such as Harpoon and SLAM-ER. Saudi Arabia operates the AGM-84L Harpoon Block II, while South Korea fields the AGM-84H SLAM-ER, giving both air forces a long-range, stand-off capability against surface and coastal targets.
This capability distinguishes them from the U.S. Air Force’s F-15E fleet, which does not carry Harpoon or SLAM-ER as part of its standard inventory.
Operational use of Harpoon from the F-15 is rarely seen in public. One notable exception occurred in 2021, when Saudi F-15SAs employed Harpoon missiles during a joint Pakistani–Saudi exercise. In that event, multiple weapons were reportedly fired after a long-distance flight from Saudi Arabia to a launch area off the coast of Pakistan, demonstrating both range and expeditionary maritime strike capability.
Such exercises provide valuable insight into how regional air forces envision the use of air-launched anti-ship missiles in contested environments, particularly in chokepoints and littoral regions.
Qatar has also been linked to potential Harpoon integration. Following Doha’s procurement of the F-15QA Ababil, reports suggested that Qatar was working to acquire the AGM-84L Block II. The F-15QA is derived from the F-15SA design and therefore includes many of the same systems and growth provisions, including the potential for an anti-ship role.
However, it remains unclear whether Qatar ultimately acquired Harpoon missiles, and no public confirmation has been made regarding operational integration.
Even without Harpoon, the U.S. Air Force’s F-15 fleet may eventually gain a powerful anti-ship capability of its own. In 2025, NAVAIR announced its intention to negotiate a contract for integrating the AGM-158C-1 Long Range Anti-Ship Missile (LRASM) on both the F-15E Strike Eagle and the F-15EX Eagle II.
Compared to Harpoon, LRASM represents a generational leap. Developed by Lockheed Martin, the missile is designed for operations in highly contested environments and incorporates low-observable shaping, advanced sensors, and autonomous targeting features. The manufacturer states that LRASM has a range in excess of 200 nautical miles, or roughly 370 kilometers, significantly outranging most legacy anti-ship weapons.
Integration of LRASM would provide the F-15 with a flexible, long-range, advanced anti-surface capability capable of holding high-value maritime targets at risk while operating outside the reach of many enemy air defenses.
Despite the emergence of newer systems like LRASM, the successful completion of the Harpoon Block II Update Obsolescence Update program demonstrates that legacy weapons can remain operationally relevant when thoughtfully modernized.
For the U.S. Navy and its partners, HIIU ensures that Harpoon remains a credible option for both maritime and coastal strike missions, particularly in scenarios where numbers, interoperability, and cost-effectiveness matter as much as cutting-edge stealth.
The January 16 test not only validates the technical success of the HIIU effort, but also reinforces the continuing importance of adaptable, multi-mission weapons in an era defined by complex littoral operations and evolving maritime threats.
