The Istanbul-Sofia Express (Turkish: Istanbul-Sofya Ekspresi, Bulgarian: Истанбул-София Експрес, Istanbul-Sofiya Ekspres) is an international passenger train operating daily between Istanbul, Turkey and Sofia, Bulgaria.

The first train departed Halkalı station at 22:40 on 21 February 2017, carrying 22 passengers.

[2] Train 493/81031 departs Sofia Central Station at 21:00 (EET) each day,[3] while its counterpart, train 492/81032, departs Halkalı station at 22:40 (TRT) each day.

[3] These two trains meet at Kapıkule, on the Turkish/Bulgarian border, where customs and passport control takes place.

From Dimitrovgrad, the Bosphorus Express disconnects and heads north to Bucharest, Romania.