A short time later, fully equipped and sufficiently trained the battalion was deployed in the front line in the Bois Grenier sector, near Armentieres. Here the Battalion remained for almost seven months in what was one of the quietest sectors on the British front. The Battalion saw considerable action in the sector as they were ordered to distract attention from the preparatory operations for the attack on the Messines Ridge, further north.

In September 1917, the Battalion was taken out of the line for a rest, and was billeted in the village of Febvin Palfart. Here it remained for a month reorganising and practising the attack, special attention being paid to the method of taking "pill boxes" by encirclement. In October, the month after their sister battalion, the 1/9th had left the Ypres sector, the 2/9th set out for the Ypres salient. There it was intended that they would take part in the ongoing attack towards the village of Passchendaele, but the weather conditions were so bad that, after an attack by one of the other brigades in the Division, the offensive was finally abandoned.

The Battalion held the line in front of Langemarck for a few days at the beginning of November, sustaining a considerable number of casualties and was then withdrawn into rest. By the first week in January the Battalion was once again in its original sector at Armentieres from where a successful trench raid was carried out early in February. This was the most successful raid the Division had accomplished.

When they came out of the trenches and returned to Steenwerck, they joined the draft from the 1/9th which had been split up when the divisional structure was altered from four infantry battalion per brigade to three. Back to full strength for the coming battles of 1918, many men would have been reunited with men they had trained with earlier in the war.

The first few months after the reamalgamation of the Battalion were spent in the Armentieres, Houplines, and then the Estaires sector and when the German advance against the 5th Army began on 21st March 1918, the 9th King's were in the line in the Fleurbaix sector and so were spared the brunt of the attack which was falling on their comrades of the 55th Division which was hard pressed in the Givenchy sector.

This was a time of great pressure and the battalion was constantly on the move, hastily preparing defences as the Germans appear capable of adviancing almost at will. Consequently, morale was low.

In May and June, the 9th King's were in the Gommecourt sector, just north of the Somme battlefield and a few miles south of the positions they had occupied at Wailly, two years earlier.

On the 28th August the Battalion attacked the village of Riencourt which was part of the formidable Hindenburg Line defences. The battalion achieved some success, but as always losses were high and as a temporary measure "A" and "C" Companies, now sadly depleted in numbers, were united to form "X" Company, while "B" and "D" Companies formed "Y" Company. This scheme was adopted so that the original companies and platoons would not sink their identities in that of a sister company.

On 1st September the famous Drocourt Queant Switch, the last and perhaps the strongest line of resistance of the enemy, was completely broken. Months had been spent on its preparation and in making concrete machine gun emplacements and belts of barbed wire, and its fall in one day was remarkable.

On the 27th September, 1918, the Battalion took part in the general advance behind the now defeated and demoralised German Army. However, stout resistance was put up by the German rearguard and progress was not at all easy.

The pressure on the retreating enemy did not let up and the battalion reached Lille on 17th October amd Tournai on the 24th. The war was almost over and when the Armistice came on 11th November, 1918 the men of the Battalion must have spent some time looking back over the months and years that they had been in France, reflecting on the friends they had lost.

The work wasn't over even though the killing had stopped and there was much to be done before the men of the 9th King's could go home. They were involved in salvage work in the Arras area and it was only in January 1919 that demobilisation began and in small parties, the men began the journey home for the last time.