Babeldaob is located northeast of Koror Island, and its northern portion contains the site of the new national capital, Ngerulmud.

[4] First sighting of Babeldaob, Koror and Peleliu recorded by Europeans was by the Spanish expedition of Ruy López de Villalobos at the end of January 1543.

[5] In November and December 1710 these three islands were again visited and explored by the Spanish missionary expedition commanded by Sargento Mayor Francisco Padilla on board of the patache Santísima Trinidad.

Two years later they were explored in detail by the expedition of Spanish naval officer Bernardo de Egoy.

As a consequence of the Spanish–American War, Spain sold Palau (including Babeldaob), the Carolines and the Northern Marianas (except Guam) to the German Empire for 17 million goldmark pursuant to the German–Spanish Treaty (1899).

In the early months of World War I, Imperial Japan occupied all German islands north of the equator.