The mouth of the Fly River was discovered by Europeans in 1842, and there was considerable contact between the Kiwai and European explorers, traders, and missionaries during the second half of the nineteenth century. By the time Landtman arrived in 1910, many Kiwai men spoke Pidgin English and had worked on pearl-shell boats in the Torres Strait and on plantations farther to the east on the southern coast of New Guinea. In 1884, the British established the protectorate of British New Guinea along the southern coast of New Guinea, and, in 1905, the southeastern quarter of New Guinea became the Australian Territory of Papua. Since 1975, the Kiwai have been citizens of the Independent State of Papua New Guinea.
The cultural similarities and differences both among the speakers of Kiwaian languages and among the Kiwai and their neighbors have not been well documented. Nonetheless, there appear to be broad cultural similarities between the Kiwai and the Marind-anim who live farther west along the southern coast of New Guinea and between the Kiwai and the Gogodala who live along the Aramia River to the west and northwest of the Kiwai.