The fort was built by the Portuguese as part of the fortifications in the Persian Gulf. Historical sources mention that Imam Nasir ibn Murshid al-Yarubi wanted to capture the fort when he sought to strengthen his control over Sohar and its fortress in 1043 AH (1633 AD).

The fort is surrounded by a wall measuring 64 meters in length and 62 meters in width, rectangular in shape, built from stones and clay. The main entrance is a round tower with a wooden door inscribed with writings, 170 cm wide and 320 cm high. Inside it stands a ratchet (rotating wheel) used to throw incendiary mixtures at attackers.

There is a staircase made of sandalwood in the entrance tower. The tower's height is 890 cm, and its diameter is 370 cm. Its first floor includes five horseshoe-shaped rooms, four of which have small windows with round arches, and the tower’s roof is made of sandalwood with openings for lighting and ventilation. The thickness of the walls varies, and the door leading to the roof is closed by an arch 135 cm high and 68 cm wide.

Next to the main entrance, in addition to the round tower, there are two towers in the northeastern part of the fortification, 605 cm high and 470 cm in diameter. The entrance leading to the roof has a boat-shaped arch 110 cm high and 80 cm wide, and there is a room on the first floor.

There is also another entrance to the fortress, which features a covered corridor called “Sabah,” topped with three large boat-shaped arches. There are four towers of the same size and height, connected by a corridor 115 cm wide. There is also a small mosque decorated with stucco inscriptions and geometric circles.

Sources:

https://www.omanobserver.om/article/1534/Features/dibba-al-seba-fort-bravely-guarding-musandam-against-the-tides-of-the-sea-of-oman