P-8A Poseidon: What is the RAF's submarine hunter aircraft?

Watch: Meet the RAF's submarine hunter.

The Royal Air Force's maritime surveillance and patrol aircraft – the Poseidon P-8 – has been busy since the new submarine hunter fleet was completed last year. 

Known by the RAF as the Poseidon MRA1, the long-awaited replacement for the venerable Nimrod has a varied role, from anti-submarine warfare operations to surveillance to search and rescue.

The 2022 arrival of the final jet at RAF Lossiemouth means that the RAF possesses a full maritime patrol fleet for the first time since 2010.

In June, the P-8 Poseidon took part in exercises with the US Navy's newest and most advanced aircraft carrier, USS Gerald R Ford, off the Norwegian coast.

As well as being designed to "enhance combined interoperability", the RAF said the exercises were for developing "the ability to maintain agile, capable, and expeditionary forces with the ability to flexibly operate within the High North region".

Earlier the same month, the RAF announced a Poseidon, along with other British aircraft and naval vessels, was deployed to monitor and shadow a Russian task group sailing close to the UK.

Last year, saw the multi-role maritime patrol aircraft assist in the rescue of rowers stranded in the Atlantic Ocean.

Watch: MOD footage shows Poseidon rescue 800 miles off UK coastline.

Role and capabilities 

P-8As are equipped with sensors and weapons systems designed for anti-submarine warfare, and will also carry out surveillance and search and rescue missions, says the RAF.

They fill the role left by the RAF's previous maritime patrol aircraft, the Nimrod, which was retired in 2010. 

Based on the Boeing 737-800 airliner, the contract to develop the P-8A for the United States military was granted in 2004, and the first Poseidon flew in 2009.

According to the RAF: "The Poseidon's comprehensive mission system features an APY-10 radar with modes for high-resolution mapping, an acoustic sensor system, including passive and multi-static sonobuoys, electro-optical/IR turret and electronic support measures (ESM)."

Watch: RAF's submarine hunter fleet is complete with arrival of ninth P-8A Poseidon.

The US Navy began operating the P-8A in 2013 and variations of the aircraft are in service with the Indian Navy and the Royal Australian Air Force.

The RAF received its first P-8A in October 2019 during a ceremony in the United States. Eight more aircraft have followed, with the fleet costing the UK £3bn in total.

Ahead of the arrival of the Poseidon fleet, RAF Lossiemouth in Moray, Scotland, underwent an upgrade costing £360m in total which included a major revamp to the airfield and the construction of a new facility.

2020 saw the conclusion of a £75m runway resurfacing scheme.

The aircraft is equipped with a range of search and tracking systems, including:

  • An APY-10 radar providing high-resolution mapping.  
  • An acoustic sensor system.
  • An IR turret and electronic support measures (ESM).

It also carries torpedos.

Watch: An RAF Poseidon flies with the Red Arrows for the first time.

Expert's view

Defence analyst Tim Ripley, from Jane's Defence Weekly, told Forces News in 2020: "For 10 years, the RAF has not had a maritime patrol aircraft so this is a major development.

"It is a different type of maritime patrol aircraft. It's not built in the way that the Royal Air Force has operated maritime patrol aircraft in the past.

"It's a converted airliner, so it's not designed to operate at a low level, which is the way that previous generations of British maritime patrol aircraft have operated," he added.

Tim Flood, from Boeing, told Forces News: "All the aircraft were delivered on, or ahead of, schedule and that was even during the pandemic where we had challenges, and the aircraft declared initial operation capability virtually months after the aircraft started arriving.

"They (RAF) received all nine aircraft and the feedback... has really helped secure the borders, secure the sort of undersea domain."


  • Powerplant: Two 27,000lb st (120kN) CFM International CFM56-7 turbofan engines
  • Length: 129ft 6in (39.5m)
  • Height: 42ft 9in (13.03m)
  • Wingspan: 123ft 6in (37.7m)
  • Maximum take-off weight: 189,200lb (85,820kg)
  • Maximum speed: 490kt (907km/h)
  • Ferry range: 4,500 miles (7,242km)
  • Service ceiling: 41,000ft

Join Our Newsletter


Amazing view from RAF Voyager supporting Typhoons from XI Squadron

Gurkha recruits face chemical attack test in most arduous training to date

Veterans wear long-awaited Nuclear Test Medals in public for first time