Mehmed Necati Efendi (d. 1793) was an Ottoman official who was appointed as secretary to the Ottoman commander-in-chief of the Crimea during the Ottoman-Russian War of 1768-1774. After he was taken prisoner with a large group of Ottoman officials, he spent ca. four years in Russian captivity in St. Petersburg, only to regain his freedom after the Peace of Küçük Kaynarca in July 1774. Having returned to Istanbul, Necati Efendi wrote his memoirs on his detention on Crimea and then in St. Petersburg. Although regular Ottoman envoys to eighteenth century Russia wrote a number of embassy reports or comparable records, Necati’s memoires are the only known captivity narrative on this country from that period. As a historical source, the text is a unique document on the Ottoman-Russian relations and conflicts in the second half of the eighteenth century. From a Transottoman vantage point, this paper examines early modern war captivity as a special form of human mobility, which took place in the space between the Ottoman and the Russian Empire. It deals with the question how far Necati Efendi, as an Ottoman official, was able to narrate his forced mobility, i.e. the captivity, as an individual experience. As mobile actor and a war captive, he was not acting between clear-cut borders of the “self” and “others”, but in intertwined spheres, and eventually in his first-person narrative he reflects these multiple levels and dynamic processes. Furthermore, a close reading of this source contributes to a better understanding of the phenomenon of war captivity as a specific form of mobility dynamics as well as of inter-imperial relations and diplomacy in the Transottoman space in the eighteenth century.