The 25th Independent Mixed Regiment (25th IMR) was one of a group of ten such units raised in Japan during June and July 1944.
The 2nd Battalion subsequently arrived at Labuan, and was ordered to march across the interior of Borneo rejoin the rest of the regiment due to a shortage of shipping; it eventually reached Sandakan.
[4] Soon after arriving on the mainland, the 25th IMR was ordered to march across Borneo to the Brunei Bay area with the 56th Independent Mixed Brigade.
[4] This required the soldiers to march on tracks for hundreds of kilometres through mountainous jungle with inadequate food supplies.
[4][6] After reaching Sandakan, the company began an overland march to re-join the remainder of the regiment, and was at Ranau at the end of the war.