On August 4, 1914 Britain declared war on Germany, sending out a call to every part of the British Empire to aid her in defeating the enemy. The Kingdom of Tonga, far away in the South Pacific, which was not a member of the British Empire, but had signed a Treaty of Friendship with Britain, became gradually involved in the war effort. Several Europeans living and working in Tonga returned to their homelands of Australia or New Zealand, to join the military forces there. Other Europeans who had been born in Tonga, but were now living in their parents’ homelands, including several sons of former Wesleyan missionaries in Tonga, enlisted in the Australian Forces.
In early 1916 a recruiting party from the New Zealand Army was sent to Tonga, and returned later in the year with recruits, some of mixed Tongan and European ancestry. These men enlisted in New Zealand, some in the Pioneer Maori Battalion, some in the Auckland Infantry Battalion.
In May 1916, the British Consul in Tonga conducted a listing of all the enemy aliens residing in Tonga. This list of 150 included Germans, Samoans, men from the New Guinea islands, and their wives and families - all German subjects. The Tongan Government placed restrictions upon these people, and a few were deported to New Zealand as prisoners of war.
Most of the men from Tonga served in the New Zealand Expeditionary Force. Several of the 1916 recruits ended up fighting in the Battles of Messines and Passchendaele on the Western Front in 1917.
Some, particularly those who were part-Tongan, enlisted in the Maori Battalion, whereas others, who were mainly European, enlisted in other New Zealand regiments. However, in several cases, one brother would enlist in the Maori Contingent, another probably in the Auckland Regiment. Some enlisted first in a general regiment, then later transferred to the Rarotongan Contingent.
Throughout the war, money was raised either as donations or in charity events and sent to the Prince of Wales Relief Fund in Britain, and other relief funds. The total amount raised in 1915 was about £1000.
In 1923, a War Memorial commemorating the men from Tonga who had served in the Great War was erected at Pangai Si`i, in Nuku`alofa. The names were collected by the Returned Servicemens Association of Tonga. Not all the men from Tonga were included, only those whose names had been submitted to the organizing committee. Queen Salote unveiled the Memorial on Armistice Day 1923. It has now had names from later wars engraved upon it, and is used every Anzac Day as the centre of commemoration in Nuku`alofa.