The ability of humans to colonize islands in the ancient past required centuries of innovation in boat construction and the development of increasingly sophisticated seafaring technologies and wayfinding strategies. Nowhere is this more evident than in the vast expanse of the Pacific, where around 3000 years ago, Micronesian and Polynesian voyagers colonized what were arguably the most remote and difficult places to reach on Earth. Because the biota on these islands evolved for thousands, or even millions of years, high rates of endemism in these environments also made them ecologically fragile. The first arrival of Homo sapiens—the ultimate adaptive omnivore—caused a wide variety of impacts that were amplified by an order of magnitude with Euro-American incursion. In this sense, as aquatically bounded places, islands serve as model systems and microcosms for how humans have affected the earth’s biosphere in the modern age. In this chapter, I document how the first island colonizers caused certain levels of ecological destruction, using Hawaiian and New Zealand birds as primary case studies. However, I take this concept further, suggesting that the processes involved in the prehistoric colonization and settlement of islands is also a corollary for how we can view the earth and future efforts to colonize other planets. Humanity is at a global tipping point, with unsustainably high human population impacts, habitat destruction, climate change, and recent pandemics. As the possibility of extraplanetary migration becomes an increasing reality—perhaps a necessity to ensure our survival—what lessons can be learned from the anthropological and archaeological study of islands as we seek new lives beyond terra firma? What are the possible consequences for our lineage and extraterrestrial life on this planet and beyond?