Having dispatched the homeward bound ships under the command of Fernando Soarez and Ruy de Cunna, who perished by the way, Almeyda sailed on the 12th of November, 1508 from Cananor towards Diu in pursuit of Mir Husseyn. On this expedition he had nineteen vessels of different sizes, with 1600 soldiers and mariners, 400 of whom were native Malabars. All western India was alarmed at this armament, but chiefly the zamorin and Malek Azz, who had used every precaution in his power to ward off the danger. Having landed with his officers in the delightful island of Anchediva, Almeyda called a council of war, in which it was unanimously determined to attack Dabul in the first place. This city was one of the most noted on the coast105, seated on a navigable river at the distance of two leagues from the sea. Its buildings were then magnificent and stately, and it enjoyed considerable trade, the inhabitants being a mixture of Pagans and Moors, subject to Sabay king of the Decan. It was always defended by a considerable garrison, which was at present augmented by 6000 men, being in fear of an attack from the Portuguese, and new works had been raised for its defence, which were planted with cannon. On the approach of the Portuguese fleet, the inhabitants began to remove their families and goods into the country, but were forbidden by the governor under pain of death; and the more to encourage them he brought his own wife into the town, in which example he was followed by many of the principal inhabitants, whose wives were brought in from their country-houses.

On the 30th of December 1508, the fleet entered the harbour, and the troops immediately landed with the utmost promptitude, dividing into three bodies to attack three several gates at once. The Moors made a brave resistance at each attack, but the works being high, their shot flew over the heads of the assailants, who were more obstructed by the dead bodies than by the defenders or their works. Nunno Vaz Pereyra, who was sent with a detachment to force an entrance at another place, put the numerous troops who resisted him to flight after a brave resistance; but they now fled in such haste towards the mountain, though pursued by ten Portuguese only, that they tumbled over each other in their haste, and retarded their own escape. In this fight, which lasted five hours, fifteen hundred of the enemy were slain with the loss only of sixteen Portuguese. Having gained possession, Almeyda distributed his men in several quarters of the streets, with orders to keep strict guard, lest the enemy might return; which they accordingly did by stealth in the night, in order to recover their wives, children, and goods. In the morning, the viceroy gave permission to his troops to plunder the town; but this was speedily prevented by the houses taking fire, which in a few hours reduced the whole to ashes, so that the booty did not exceed 150,000 ducats. In fact the town was purposely set on fire by the private orders of the viceroy, lest the men might have been so satiated by the riches of the place as to retard his ulterior designs. The ships in the harbour were likewise destroyed by fire, to the no small risk of the Portuguese ships which were very near.

In fitting out for this expedition, the viceroy had not laid in any considerable store of provisions, as he expected to have got supplies on the coast; but on sending to the neighbouring villages none was to be had, as the last crop had been utterly eaten up by locusts, many of which were found preserved in pots for food by the natives, and being tasted by the Portuguese were found palatable, and not unlike shrimps. This made them conclude that there were land shrimps, as in some places, particularly in the vineyards about Rome, there are crabs found not unlike those of the sea. Hence if locusts were not so numerous and destructive, so as to blast the hopes of harvest and to be dreaded like a plague, they might be useful as food; and we know from Scripture that St John fed upon them in the desert.

Leaving Dabul, the viceroy proceeded for Diu, expecting to procure provisions along the coast. Payo de Sousa, having seen some cattle feeding on the banks of a river, went up the stream in his galley in hopes of procuring some; but was opposed by the natives, and he and George Guedez were both slain. Diego Mendez succeeded in the command of that galley, and while continuing the voyage towards Diu he met one of the Mameluke galleys going from Diu to Dabul, which was well manned and commanded by a courageous and experienced Turk; who, on discovering the Portuguese galley ordered all his soldiers to conceal themselves, so that Mendez immediately boarded without suspecting any danger, on which the Turks rushed out from their concealment and had almost gained the Portuguese galley; but the Portuguese recovered from their surprise, and made themselves masters of the Turkish galley, slaying every one of the enemy without losing a single man on their side. The chief booty taken on this occasion consisted of a young and beautiful Hungarian lady of noble birth, who was brought to the viceroy, and given by him to Gaspard de la India, who gave her to Diego Pereyra, who afterwards married her. Farther on, they took in the river of Bombaim, now called Bombay, a bark with twenty-four Moors belonging to Guzerat, by whose means they procured a supply of sheep and rice, while some cattle were procured in other places, and a farther supply was got at the fort of Maim, all the people flying to the mountains from terror of the Portuguese, having heard of what had happened at Dabul.

On the 2d of February 1509, the viceroy arrived at Diu, which from the ships appeared a grand and spacious place, girt with strong walls and lofty towers, all handsomely built and well laid out like towns in Portugal, which recalled in the men the memory of their own country, and animated their courage to achieve the conquest. Malek Azz the lord of Diu was at this time with his army about twenty leagues distant, making war upon the Rajaputs; but immediately on receiving notice of the approach of the Portuguese fleet, he hastened to his capital with all possible celerity. He had already used such precautions as not to excite suspicions in Husseyn of his fidelity, though little inclined to assist him, and he was now anxious not to exasperate the viceroy in case of his proving victorious. Taking into consideration the strength of the place, the courage and conduct of Azz and Husseyn, and above all that there were above two hundred vessels well manned and armed, he thought it necessary to proceed with the greatest circumspection, and accordingly it was settled in a council of war, that Nunna Vaz Pereyra should lead in with his ship, in which there were 120 fighting men, many of them gentlemen of tried valour. Pereyra was to be seconded by George de Melo, whose crew was equally numerous; after which the rest of the ships were to follow in succession, having from 80 down to 25 men in each according to their size. The night was spent by the Portuguese in anxious preparation for the approaching conflict, by exercises of religion and putting their arms of all kinds in order.

Between nine and ten next morning, when the tide had risen sufficiently to float the ships over the bar, the viceroy gave the signal for entering the port in the appointed order, and the fleet moved on amid the noise of loud shouts and the din of warlike instruments from both sides. The vessels belonging to Malek Azz made haste to oppose the entrance of the Portuguese, and poured in a shower of bullets and arrows into the galley commanded by Diego Perez who led the way for Nunno Vaz, by which ten men were slain; yet Nunno courageously continued his course, pouring his shot among the large ships of the enemy and sunk one of them. Vaz was in great danger between two ships of the enemy, when Melo came up gallantly to his rescue, and ran so furiously upon one of these ships that he drove it up against the ship commanded by Vaz, so much disabled that it was immediately boarded and taken by the next ship in succession commanded by Sebastian de Miranda. All the ships having penetrated into the harbour, pushed on in emulation of each other who should do most damage to the enemy; while the viceroy, placing himself in the midst of the enemy, directed his shot wherever it seemed most calculated to annoy the enemy and to aid his own ships. In this manner the action continued to rage for some time with reciprocal courage and violence, till at length the paraos belonging to Calicut fled along the coast, giving out every where that the Rumis or Mamelukes were victorious.