How did New Zealand gain control of Western Samoa during World War I?

New Zealand gained control of Western Samoa during World War I through a military occupation followed by a formal international mandate.

In August 1914, at the beginning of the war, a New Zealand force—supported by Australian, British, and French warships—occupied Western Samoa. This operation met no resistance from the local German or Samoan populations.123

Following the defeat of Germany in the war, the League of Nations established a mandate system to govern former German colonies. In 1920, the League granted New Zealand a mandate over Western Samoa, authorizing it to administer the territory. This arrangement was part of a broader distribution of territories among the Allied powers, intended to manage regions deemed not yet ready for self-governance.423