It was initially put into service by the Royal Air Force shortly before the outbreak of the Second World War and primarily operated by it thereafter.

[1][2][3] The Hudson served throughout the war, mainly with Coastal Command but also in transport and training roles, as well as delivering agents into occupied France.

[4] This attracted the interest of various air forces and in 1938, the British Purchasing Commission sought an American maritime patrol aircraft for the United Kingdom to support the Avro Anson.

[7] Due to the United States' neutrality at that time, early series aircraft were flown to the Canada–US border, landed, and then towed on their wheels over the border into Canada by tractors or horse drawn teams, before then being flown to Royal Canadian Air Force (RCAF) airfields where they were then dismantled and "cocooned" for transport as deck cargo, by ship to Liverpool.

[10] A PBO-1 Hudson of the United States Navy squadron VP-82 became the first US aircraft to destroy a German submarine,[11] when it sank U-656 southwest of Newfoundland on 1 March 1942.

U-701 was destroyed on 7 July 1942 while running on the surface off Cape Hatteras by a Hudson of the 396th Bombardment Squadron (Medium), United States Army Air Forces (USAAF).

Its opponents found that the Hudson had exceptional manoeuvrability for a twin-engine aircraft; it was notable for the tight turns achievable if either engine was briefly feathered.

High-scoring Japanese ace Saburō Sakai, praised the skill and fighting abilities of an RAAF Hudson crew killed in action over New Guinea after being engaged by nine highly manoeuvrable Mitsubishi A6M Zeroes on 22 July 1942.

In 1997, Sakai wrote formally to the Australian government, recommending that Cowan be "posthumously awarded your country's highest military decoration".

3 Squadron, Royal New Zealand Air Force (RNZAF) Hudson Mk IIIA, NZ2049,[16] (41-46465) after spotting an enemy convoy near Vella Lavella, was engaged by three Japanese floatplane fighters.

After skilled evasive manoeuvring at an altitude of less than 50 feet (15 metres), by the Hudson's captain, Flying Officer George Gudsell,[17] the crew returned with no casualties to Henderson Field, Guadalcanal.

[20] The type formed the basis for development of the Lockheed Ventura resulting in them being withdrawn from front line service from 1944, though many survived the war to be used as civil transports, primarily in Australia and a single example was briefly used as an airline crew trainer in New Zealand.