The office and mosque of Bilal al-Habashi is located on the southwestern side of the Great Mosque of Mersin. The great companion Bilal al-Habashi is the muezzin of the Prophet Muhammad, and in honor of him and a reminder of his important role in the call, his office was built in the seventh century, and his mosque was built in the sixteenth century, where he recited the call to prayer and the mother of prayer in the place called Kerkashik, when he came to Mersin during his visit to the sites of conquests Islamic. It is a mosque with a black plan and covered with a large dome. It includes a portico with three sections and three domes. Inside, there is a shrine section belonging to Bilal al-Habashi. In addition, a well was built next to the mosque.