The maritime-specific UAVs will be operated from Royal Navy and Royal Fleet Auxiliary ships to gather intelligence and survey areas of operation.
"ScanEagle provides the Royal Navy with proven surveillance capability that has already been used on operations by other nations, so we know we are getting top quality equipment," said Minister for Defense Equipment, Support and Technology Philip Dunne. "The technology is off-the-shelf and will be available to the Royal Navy as soon as possible.
"Our continued investment in intelligence, surveillance and reconnaissance systems is essential to keeping our armed forces up-to-date with the latest capabilities and this will be a central part of the Ministry of Defense's investment in new equipment over the next 10 years."
The ScanEagle UAV, with its surveillance payload, weighs about 38 pounds. It has a maximum speed of 55- to 80 mph and a flight time of more than 20 hours. It is launched by catapult.
The value of the contract is about $46.4 million, Britain's Ministry of Defense said.