First siege of Diu
Part of the Ottoman–Portuguese conflicts and Gujarati–Portuguese conflicts
Date 16 February 1531[1] Location Diu, Gujarat Sultanate Result Ottoman–Gujarati victory
Belligerents
Ottoman Empire Gujarat Sultanate	Portuguese Empire
Commanders and leaders
Khoja Zufar Mustafa Bayram	Nuno da Cunha
Strength
10,000[2]–12,000 men[3] 2 galleons[4] 70 oarships of various sizes[4] several basilisks[5]	About 400[6][7][8] vessels: 14 galleons[9] 6 naus[9] 2 war caravels[9] 5 large supply junks[9] 2 galleasses[9] 12 galleys[9] 16 half-galleys[9] 228 light-galleys[9] 115 small craft and merchantships[9] 30,000 men,[10] including: 3,560 Portuguese soldiers[11] 2,000 Malabarese auxiliaries[11][12] 8,000 combat slaves[11][7] 3,000 slave gunners[11] 1,450 Portuguese sailors[11][12] 4,000 Malabarese sailors or rowers[11] 800 junk ship crew[11]
Casualties and losses
800	31 dead[13] 120 wounded

The siege of Diu occurred when a combined Ottoman-Gujarati force defeated a Portuguese attempt to capture the city of Diu in 1531. The victory was partly the result of Ottoman firepower over the Portuguese besiegers deployed by Mustafa Bayram, an Ottoman expert.^[14]

Shortly before the siege they encountered roughly 800 enemy soldiers at Siyâl Bet island^[a], engaged them in combat, and killed them all.^[15] There were 9^[16] or 17 Portuguese killed and 120 wounded.^[17] They then sailed for Diu, but the Muslim alliance defeated them and killed 14.^[18]

Although Diu was successfully defended, victory was short-lived: Diu was blockaded and the Portuguese armada was diverted towards more exposed Gujarati cities.^[19] Ghogha, Surat, Mangrol, Somnath, Bassein, Tarapur, Kelva, Mahim, Bulsar, Agashi, Patam, Pate, and many smaller settlements were assaulted and sacked, some never recovering from the attacks.^[20][21][12]

In 1534, Sultan Bahadur of Gujarat signed a peace treaty with Governor Nuno da Cunha, granting the Portuguese the territory of Bassein, including Bombay. In 1535, the Portuguese were allowed to construct a fortress at Diu.

• Siege of Diu (1538)
• Siege of Diu (1546)

• ^[a] Gujarati name for jackal island, one of three islands near Diu, João de Barros calls it Ilha de Bet.

20°43′N 70°59′E / 20.71°N 70.98°E / 20.71; 70.98