It has been used as a harbour since at least Roman times. The natural harbour has been greatly improved with extensive docks and wharves, and has been massively fortified.

Malta's 16^th Century capital Valetta stands on a promontory flanked by two mayjor harbours: Grand Harbour and Marsamxett Harbour.

 Situated on the Crossroads of the Mediterranean , the  little  island has played a leading role in the vicissitudes and the ups and downs of the history of the Middle Sea. But the island owes much of its history of its natural harbours. To the 21^st –century cruise liner passenger , Valletta`s Grand Harbour offers an impressive spectacle not easily equalled by the harbours along the Mediterranean littoral. The powers that were looked on Malta as a key harbour in the Mediterranean Sea not only because of its strategic and military position but also as a leading commercial port for entrepot trade. 

At one time or other the traders of yesteryear- the Pheonicians and the Carthaginians, the Romans and the Saracens, the Normans, the Normans and the Aragonese, the hospitalier Knights, Napoleon and Nelson- have used Malta's Harbours. It was the Pheonicians who gave the island the name Maleth ( a haven), which was later corrupted by the Greeks into Melita (honey), from which the modern name of Malta derives. 

When Emperor Charles V offered Malta to the Knights of St. John in 1526, the island came into the limelight as a possible place where the Knights could re- establish themselves permanently after the loss of Rhodes, the island of Roses, in 1522. An eight-man commission was dispatched to Malta to report on the nature of the island.

The commissioners reported :
“The island of Malta is only one continued rock of soft sand stone…the surface of the rock is stony, unfit to produce corn…except for a few springs in the middle of the island, there is no running water…wood is scarce…but…there are several ports or capes and places that form a sort of bays and coves in which ships may anchor; there are two spacious and very good harbours in the island , capable of receiving the largest fleet… The convenience of so many ports , so convenient for the armada of the Order , make us be of the opinion that the Emperors proposals ought not to be rejected.”

At the time , the Order's fleet was based in the Roman port of Cittavecchia. In October 1530 the Knights entered Malta's main harbour on board the great carrack Santa Anna- the first ever armour-plated vessel  under the command of Sir William Weston, who had commanded the Santa Maria as the Order pulled out of Rhodes eight years before. 

Valletta's harbours were bereft of their fortifications, except for Fort St. Angelo , where the Order took up abode. The Knights , whose service was on the sea, and who had accepted Malta only because of its fine natural harbours, preferred to settle in the small fishing village of Birgu, just inside Grand Harbour. A  landmark on the Grand Harbour basin is the vedette on Senglea Point bearing the figures of an ear and an eye- symbols of the hearkening ear and the watchful oculus.

Francesco Balbi di Correggio , a Spanish contemporary diarist of the epic siege of Malta by Suleiman the Magnificent in 1565, wrote that the galley slaves on the Ottoman fleet transported 80 ships across the neck of land that divides Grand Harbour from Marsamxett Harbour.

Grand Harbour can tell many a brave story. It welcomed the first Grand Master in 1530, it also bid farewell to the last of the line in June 1798, as Napoleon took over the island. Having anchored inside the Grand Harbour on board his flag ship L’Orient, Napoleon could well exclaim: “Nousavons dans le centre de la Mediterranean e la place plus forte de L’Europe”

Lord Nelson was the next man to follow in 1800. The British era was marked with many an outstanding event. Valletta`s harbours became the base station of the English Mediterranean fleet, and continued to develop as a nava base with its docks.

During the Crimean War in 1854 Malta served as an important military station and a supply depot of feedstuffs and ammunition, as a repairing yard, and as a base hospital. It was an important military  station, and a supply depot of foodstuffs and ammunition, as a repairing yard, and as a base hospital. It was an important bunkering station. Local papers carried the news of Florence Nightingale's stop in Valletta on her way to Scutarie. “The party landed and visited the objects in Valletta most worthy of notice.” (Malta Times) Visiting Malta in mid 19^th century, William Tallack wrote:” Malta is a principal link between Eastern and Western worlds; and although of an area scarcely exceeding that of the Isle of Wight, is one of the most interesting and important of all islands. Besides being the principal station of the British fleet in the Mediterranean, it is daily visited by ships of all nations, and especially by the fine steamers of the peninsular and Oriental mail company, and those of the Austrian Lloyd`s and the French Messageries Imperiales.” In those days constant communication inside the harbours was kept up throughout the day by numerous boats and ferries. In 1910 Thomas Rowley mused: “ In a little springing dghaisa, we can cross as quick as a ferry.”

In former times on the natural islet within Marsamxett Harbour there was the Lazzaretto, facing Valletta across the sea. Travellers had to undergo quarantine on their arrival. During his second visit to Malta in 1811 Lord Byron carved his name among the graffiti on one of the terraces of Lazzaretto. Rev.(later Cardinal) John Henry Newman, while undergoing quarantine in 1833, hired a violin that sounded “grand” in his spacious apartment.

A focal point within marsamxett harbour is the 18^th century massive fort Manoel, known after its founder the Portuguese Grand Master Manoel de Vilhena. This harbour is now developed as a major yacht marina hub.

A landmark on Valletta itself, as seen from Marsamxett Harbour side, is St. Paul's Anglican Cathedral with its smart, elegant behind the bastions. It was built in 1839 on the initiative of the Dowager Queen Adelaide of William IV of England, who was wintering  in Malta for health reasons.