It will also create 150 jobs in the UK, most of them at Lossiemouth but with others at sites in Bristol, Yeovil and Gosport.
Defence Secretary Ben Wallace said: "Our new Poseidon fleet continues to grow from strength to strength and is already defending the UK's maritime interests at home and abroad.
"This contract with Boeing Defence UK secures our critical submarine-hunting aircraft capabilities."
Scottish Secretary Alister Jack said the new jobs showed the "benefits UK defence investment brings to Scotland".
"The Moray station's fleet of Poseidon submarine-hunting aircraft are vital to maintaining the security of the UK and our NATO allies," he added.
"The prosperity generated by defence employment in Scotland, alongside the UK Government's Plan for Jobs, will help us build back better from the pandemic."
What is the P-8A Poseidon?
Specialising in anti-submarine warfare, the P-8A Poseidon is the RAF's multi-role maritime patrol aircraft.
It is expected to be used to identify and track potentially hostile submarines operating around UK waters.
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.
The Royal Air Force welcomed the first of its new P-8A Poseidon maritime patrol aircraft to RAF Lossiemouth in November.
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).
- Capacity to carry torpedoes.
RAF Lossiemouth in Moray, north-east Scotland, is one of two RAF Quick Reaction Alert (QRA) stations that protect UK airspace.
The station is made up of four Typhoon combat aircraft squadrons, one Poseidon MRA1 squadron, and an RAF Regiment squadron.
Aircraft and crews are maintained on high alert in order to scramble and intercept unidentified aircraft approaching UK airspace.
RAF Lossiemouth personnel and aircraft also support operations worldwide and host numerous national and international exercises.
Cover image: MOD.