Archaeological evidence from Islamic era reflects trade contacts and flourishing commerce in the Persian Gulf. Indeed, some regional infrastructures surviving from Sassanian times could have acted as the basis for these interactions. Mahruban is one of the most important ports in the Persian Gulf with evidence of extensive trade contacts with such neighboring ports as Basra, Siniz and Ganaveh on the one hand and the Gulf’s northern hinterlands such as Arjan in Behbahan region on the other. The few available data on the port prior to the recent excavations was confined to written documents by early Islamic historians and a number of more recent references by Schwarz and Rawlinson. Given the great potentials of the port for increasing our understanding of the Iranian sea trade during Sasanian and in particular the early Islamic era, the excavation project was designed with the aim of determining its sequence and detecting the remains related to sea trade through the study of archaeological material. The present paper reports the provisional results of the excavation in Trench B at Mahruban, and combines them with the available written evidence in order to define its current location and its role in the trade ties through the Persian Gulf. The preliminary analyses show that ceramic assemblage from the trench parallels the material from Suhar in Oman, Ras al-Khaima in the UAE and Qal’at in Bahrain as well as such Iranian centers as Susa in Kuzestan and Siraf in Bushehr. In this paper, a location near the modern Deylam port is discussed and finally suggested for this historical harbor based on comparison of the archaeological finds with the historical texts from early Islamic period.