Embarked at Wellington with 32nd Reinforcements on 22 November 1917 and disembarked at Liverpool on 7 January 1918. Marched in (Sling) Auckland Infantry Regiment (Reserves) on 8 January 1918 and left for France on 20 March 1918. Marched into camp (Etaples) on 24 March 1918. Marched out to 1st New Zealand Entrenching Battalion (Etaples) on 26 March 1918.

Joined 2nd New Zealand Entrenching Battalion in the field on 29 March 1918. Reported missing 12-19 April 1918. In May 1918 reported wounded (bullet left thigh) and a prisoner of war in Germany. Released and arrived Ripon, England 9 January 1919. Embarked Plymouth for New Zealand on 18 March 1919.

Discharged 28 May 1919 but re-enlisted with New Zealand Army Ordnance Corps on 14 July 1919.

Watson may well have belonged to one of the Otago companies in 2 Entrenching Battalion and been one of the more than 200 Otago troops that were taken prisoner of war on 16 April 1918.

“On April 15th the enemy attacked and enveloped the town of Bailleul. At daybreak on the 16th the sweep was continued in strength against Meteren. The 2nd Entrenching Battalion at once became heavily involved. At this stage half the strength of the 1st Otago Company of the Entrenching Battalion was disposed along with Canterbury mainly to the right of Meteren; the 2nd Company of Otago and the remaining strength of the 1st Company were disposed with English troops to the left front.

With the fall of Bailleul and the anticipated continuation of the enemy's advance towards Meteren, it was notified that the English troops still further to the left would probably retire down the valley. In that case the New Zealand troops on the left of Meteren were to conform by withdrawing to the newly constructed switch trench in rear of the village. The withdrawal by the English troops did eventuate during the night; but they failed to advise the adjoining posts of their action. …

The German attack, preceded by heavy machine gun fire, developed about daybreak. The enemy, meeting no resistance on the left, immediately exploited his initial success. It was not long before our positions were under fire practically from three sides. The opportunity for effecting a withdrawal had now passed. The platoon of the 1st Company of Otago, commanded by Sergt. T. Sounness, endeavoured to get clear by forcing its way along the Bailleul-Caestre Road, but failed. The two platoons of the 2nd Company, now heavily pressed by the enemy, their ammunition practically expended, and all avenues of escape closed, decided that in the circumstances their only alternative was to comply with the demand for surrender. Thus three platoons, or a total of 210 other ranks, fell to the enemy as prisoners.” [pp 305-06, Byrne, A E “Official History of the Otago Regiment, N.Z.E.F. in the Great War 1914-18”, J Wilkie & Company, 1921]