The Iskele Mosque in Istanbul’s Kadıköy district stands among the significant imperial works of the city, distinguished by its historical background and its contribution to the area’s development.

Commissioned by Ottoman Sultan Mustafa III in 1761 and originally built along the shoreline, the mosque lost its waterfront (yalı mosque) characteristic following land reclamation works carried out along the Kadıköy coast during the late Ottoman period.

Architecturally, the mosque features a square plan with a central dome. It was heavily damaged in a fire in 1853 and later underwent extensive restoration and reconstruction in 1858 during the reign of Sultan Abdülmecid.

Also known as the "Sultan Mustafa III Iskele Mosque,” the present structure reflects the characteristics of its 19th-century renovation rather than its original 18th-century design.

Beyond serving as a place of worship, the mosque played a key role in Kadıköy’s settlement process. Although the Osman Ağa Mosque already existed in the area, the construction of an imperial mosque significantly influenced the district’s development and population growth.

Today, the Iskele Mosque remains one of the prominent historical landmarks in Kadıköy, attracting attention as one of Istanbul’s notable coastal mosques due to its location and architectural features.

Dr. Kubilay Arpacı, a research assistant at Istanbul Medeniyet University’s Faculty of Arts and Humanities, Department of Art History, Division of Turkish and Islamic Art, stated that the Iskele Mosque is an important structure in terms of Kadıköy’s historical development.

Arpacı noted that Sultan Mustafa III, who commissioned the mosque, also built the Laleli and Ayazma mosques and reconstructed the Fatih Mosque after it was heavily damaged in an earthquake, yet did not attribute his name to any of these works.

He described the Kadıköy Iskele Mosque as having a modest, single-dome design, adding that its architecture, façade arrangements, and overall mass were largely renewed following the extensive restoration during the reign of Sultan Abdülmecid after the fire.

Arpacı also pointed out that the restoration inscription at the mosque’s entrance was written by Kazasker Mustafa Izzet Efendi, one of the prominent calligraphers of the period, while the imperial tughra of Sultan Abdülmecid above it was inscribed by Abdülfettah Efendi.

He emphasized that land reclamation activities along the Kadıköy shoreline altered the identity of the structure, noting that original interior decorations are limited, while baroque-style ornamentation stands out in the dome.

Arpacı explained, "Although it is called the Iskele (Pier) Mosque, there is no longer any visible trace of a pier today. This is because the area was largely filled during the Ottoman period. When we look toward the sea from the mosque now, the sea is no longer visible."

"It is highly likely that during the time of Sultan Mustafa III, the mosque originally functioned as a waterfront mosque. Historical sources also mention a primary school associated with the mosque, but unfortunately, it has not survived to the present day,” he said.

Highlighting the mosque’s importance for Kadıköy, Arpacı added that while the nearby Osman Ağa Mosque dates back to 1614, the Iskele Mosque, built in 1761 as an imperial structure, played a central role in increasing the district’s population and vitality.

"With the construction of the mosque in the 18th century, Kadıköy began to flourish demographically. In the following period, with the settlement of non-Muslim communities as well, Kadıköy evolved into one of Istanbul’s key centers of attraction,” he said.