The oldest Hawaiian Island is Kauai, which is about 5.1 million years old. The islands are forming as the Pacific Plate moves about 4 inches per year across a magma hotspot which forms volcanoes that breach the surface as it continues moving at a slow pace. The newest island is the Big Island, which formed about .7 million years ago. Over time, islands will continue forming to the East of the Big Island, with the next island known as Loihi. It’s expected to breach the ocean surface in between 10,000 and 100,00 years.