This paper is intended to update the numbers of foreign fighters traveling to join the so-called Islamic State and other violent extremist groups in Iraq and Syria provided by The Soufan Group (TSG) in June 2014. Since then, other reports have emerged, including in September 2015 when United States intelligence estimates put the number of foreign fighters in Syria at upwards of 30,000 from over 100 countries. TSG research, which includes information provided directly by officials, largely confirms these figures.