| Regimental number | 27461 |
| Date of birth | |
| Place of birth | Winton |
| Religion | Presbyterian |
| Occupation | Farmer |
| Marital status | Single |
| Age at embarkation | 24.7 |
| Height | 5' 9.5" |
| Weight | 158 lbs |
| Next of kin | Father, W G Coster, Waituna, Southland |
| Previous military service | Nil (previously rejected for NZEF enlistment on account of being medically unfit) |
| Enlistment date | |
| Place of enlistment | Trentham |
| Rank on embarkation | Private |
| Unit name | New Zealand Expeditionary Force, 17th Reinforcements, Otago Infantry Battalion, D Company |
| Embarkation details | Unit embarked from Wellington on board Pakeha on |
| Final rank | Private |
| Final unit | 2nd Battalion, Otago Infantry Regiment |
| Fate | Killed in Action |
| Age at death from cemetery records | 23 |
| Place of burial | No known grave |
| Commemoration details | Tyne Cot Memorial (New Zealand Apse, Panel 3), Zonnebeke, Belgium |
| Miscellaneous information from cemetery records | Parents: William Gordon Coster and Maggie Auld Coster, Waimauku, Auckland. Native of Winton, Southland, Invercargill |
| Other details |
War service: Western Front Embarked Wellington, 23 September 1916; disembarked Devonport, England, 18 November 1916, and marched into Sling Camp. Proceeded overseas to France, 9 December 1916; joined 2nd Bn, Otago Infantry Regiment, in the field, 5 January 1917, and posted to 8th Company. Admitted to No 3 NZ Field Ambulance,, 16 February 1917 (mumps), and transferred to No 7 General Hospital, St Omer; rejoined Bn, in the field, 10 March 1917. Reported missing, 12 October 1917. Court of Enquiry, 19 November 1917, concluded: 'Killed in action, 12 October 1917.' Medals: British War Medal, Victory Medal |
| Sources | Nominal Roll Vol. 2: Roll 41, p. 15 Archives New Zealand (Wellington), Agency AABK, Series 18805, File 21897790 |