Diehl Defence IRIS-T SLM Naval

History

The Diehl Defence IRIS-T SLM naval system is a German shipboard adaptation of the IRIS-T SLM medium-range surface-to-air missile system. It is being developed for the German Navy's F125 Baden-Württemberg-class frigates to strengthen their air-defence capability beyond the short-range RIM-116 Rolling Airframe Missile system.

A navalized IRIS-T SLM demonstrator was first tested from the F125 frigate Baden-Württemberg in October 2025. Following the successful demonstration, Diehl Defence and the Federal Office of Bundeswehr Equipment, Information Technology and In-Service Support, or BAAINBw, signed a contract in October 2026 for adaptation development, prototype construction and comprehensive test firings.

The program remains under development. The 2025 installation was a demonstrator rather than a finalized operational weapon configuration, and the permanent F125 installation, launcher arrangement and missile capacity have not been confirmed in the available program information.

Development and maritime demonstration

The naval adaptation originated from the land-based IRIS-T SLM ground-based air-defence system. For the Maritime Firing Exercise 2025, Diehl Defence developed an Anti-Air Warfare module and integrated it on the C-deck of the frigate Baden-Württemberg. Development from the initial concept to live firing took less than ten months.

The October 2025 exercise provided the first successful firing demonstration of a navalized air-defence system using a missile from the IRIS-T family. The system completed the established test and evaluation objectives and demonstrated successful target engagement at sea. The temporary installation was intended to prove the feasibility of shipboard operation rather than represent the final production configuration.

The firing also demonstrated integration with the frigate's HENSOLDT TRS-4D naval radar. The non-rotating TRS-4D belongs to the same medium-range radar family as the TRML-4D used with land-based IRIS-T SLM fire units. This relationship provides a technical basis for adapting existing IRIS-T SLM functions to the shipboard sensor environment.

F125 adaptation contract

In October 2026, Diehl Defence and BAAINBw signed a contract for the adaptation development of IRIS-T SLM for the F125 class. Diehl Defence is responsible for building prototypes and conducting comprehensive test firings. The work is intended to integrate the missile system into the existing architecture of the frigates and develop it into a mission-capable naval installation.

The adaptation requires more than placing a land launcher on a ship. A permanent naval system must be suitable for operation in a maritime environment and integrated with shipboard sensors, command systems, electrical supplies and weapon-control architecture. The final arrangement must also withstand continuous exposure to humidity and saltwater conditions.

Design

The naval IRIS-T SLM is based on the medium-range member of the IRIS-T surface-launched missile family. The baseline IRIS-T SLM provides an effective intercept range of about 40 km and a maximum engagement altitude of about 20 km. Its principal role is defence against air-breathing threats such as aircraft, unmanned aerial vehicles and cruise or anti-ship missiles. It is not designed to provide substantial ballistic-missile defence.

The 2025 demonstrator used an Anti-Air Warfare module installed on the C-deck of Baden-Württemberg. It represented an experimental shipboard configuration and should not be treated as the definitive production launcher. The demonstrated missile capacity was limited, while the number of missiles planned for a future permanent installation was not established by the confirmed program information.

Radar and fire control integration

During the 2025 firing exercise, IRIS-T SLM operated in combination with the F125's HENSOLDT TRS-4D radar. The naval TRS-4D and the land-based TRML-4D used with IRIS-T SLM are members of the same radar product family. This common technical lineage allows software and system functions developed for ground-based air defence to be adapted to maritime applications while retaining the ship's existing naval sensor architecture.

Role on the F125 class

The F125 frigates were designed primarily for long-duration stabilization and maritime security missions and entered service without a medium-range area or local-area surface-to-air missile system. Their missile-based self-defence is centered on the RIM-116 RAM short-range system, with 42 ready missiles and an effective range of roughly 9 km. Adding IRIS-T SLM would extend the frigates' defensive engagement envelope and provide another layer between short-range point defence and more distant airborne threats.

The system is intended specifically to improve the ability of F125 frigates to respond to modern air threats. A medium-range missile system would allow the ships to engage aircraft, drones and incoming missiles at substantially greater distances than RAM alone.

Program status

As of October 2026, the naval IRIS-T SLM program is in adaptation development for the German Navy's F125 frigates. The 2025 demonstrator successfully completed live firing at sea, but it was not an operational production installation.

The 2026 contract covers prototype construction and further test firings required for integration with the F125 architecture. Series configuration, final launcher layout, installed missile capacity and service-entry timing have not been confirmed in the supplied program information. The German Navy therefore should not yet be considered an operational user of the finalized naval IRIS-T SLM system.

Variants

• 2025 navalized system demonstrator — Experimental Anti-Air Warfare module installed on the C-deck of the F125 frigate Baden-Württemberg for Maritime Firing Exercise 2025. It completed live firing and met the defined test objectives.
• F125 adaptation — Naval configuration under development following the October 2026 contract between Diehl Defence and BAAINBw. Prototype construction and further test firings are planned as part of the adaptation program.

Specifications (2025 navalized system demonstrator)

General characteristics

• Type: Medium-range naval surface-to-air missile system demonstrator
• Manufacturer and developer: Diehl Defence
• Missile family: IRIS-T
• Host ship: Baden-Württemberg, F125 class
• Installation location: C-deck
• Radar used during testing: HENSOLDT TRS-4D

Performance

• Baseline IRIS-T SLM effective intercept range: approximately 40 km
• Baseline IRIS-T SLM maximum engagement altitude: approximately 20 km

Armament

• Missile: IRIS-T SLM surface-to-air missile
• Primary target set: Aircraft, unmanned aerial vehicles, cruise missiles and other air-breathing threats