Istanbul and Surabaya Time Zone Comparison
Istanbul and Surabaya are two major cities that sit in noticeably different time zones. Istanbul is Turkey's largest city and historic capital, uniquely straddling Europe and Asia across the Bosphorus strait. Surabaya is Indonesia's second-largest city after Jakarta and the administrative center of East Java, home to the country's most important naval port.
Istanbul is always 4 hours behind Surabaya, with no seasonal change, since neither city's daylight saving rules shift this relationship.
With a moderate gap like this, it's worth checking the suggested call window above before scheduling a meeting between Istanbul and Surabaya.