Kristen Biehl, University of Oxford, gives a talk for the Arrival Cities COMPAS Seminar Series. As of the late 1950s, Istanbul has maintained its position as Turkey’s leading arrival city for millions of internal migrants from all parts of the country, whose impact on the city’s changing physicality, diversity, imaginary and exclusions has been extensively researched within the field of Turkish urban studies. Over recent decades, however, a new form of migration composed of international migrant and refugee flows is becoming an emergent reality of Istanbul, whose transformative impact still remains little understood. This talk presents ethnographic research from Istanbul's historic Kumkapi neighborhood, which today has become a key residential and employment hub for a great diversity of migrants and refugees, whose national/ethnic/religious/gender backgrounds, migration motives and legal statuses greatly vary. It will initially set out the numerous aspects, historical and present, that have permitted this transformation, focusing throughout on processes of informalization and diversification. Ethnographic examples will then be presented in relation to the socio-spatial ramifications of these processes. In conclusion, the speaker will discuss the usefulness of the notion of arrival city as it relates to the multiple spatialities, temporalities and mobilities of Kumkapi. Creative Commons Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales; http://creativecommons.org/licenses/by-nc-sa/2.0/uk/