Enlisted in Rarotonga 1 July 1916. Disembarked ex Malwa at Suez 27 December 1916 and posted to the Training Units and Depot at Moascar. Posted to the Rarotongan Company 7 April 1917. Admitted to the 24th Stationary Hospital at Kanatara, the 27th General Hospital at Abbassia and the 66th Casualty Clearing Station from 31 August 1917 to 3 September 1917. Transferred to Aotea Convalescent Home at Abbassia 12 September 1917. Again admitted to the 27th General Hospital 12 September 1917 and discharged to duty 26 September 1917. Transferred to Rarotongan Company 27 September 1917. Admitted to hospital from 4 September 1918 to 26 September 1918. Embarked for New Zealand per SS Malta 14 December 1918 and discharged 20 March 1919.

Cook Islands Roll of Honour board at the RSA Nikao Rarotonga records his name as 'R. Mare'.

In February 2022, the headstone was located by Lydia Karena, Oki Karena and Tarerea Kimitaunga inland from Karanga Mangaia beside the Armstrong family orchards. We documented this grave in April 2023, however there was no satellite signal to capture the exact GPS coordinates.

The following information was sent to us in January 2019 by Sue McGreal, a descendent of Private Mare Ruavai:
"Mare returned to the Cook Islands at the end of WW1 having left his homeland in November 1916.
The story is told of his being mighty lucky to return and the name ‘Mareraki’ was used from then on.
He married Uaonga Paia in 1921 at Oneroa, Mangaia. They had 4 daughters and 3 sons and lived the first part of their life in Mangaia, then lived in Titikaveka in Rarotonga.
He was a planter and sometimes took work in the outer islands like Makatea to have an income. He returned to Mangaia for a few years whilst his family remained in Rarotonga. Mare died in 1949 and is buried on Mangaia. Fondly remembered by his surviving daughter, Mrs Tuku Campion, Nelson, NZ and all of his descendants in the Cook Islands, NZ and Australia."