In the 16th century, Šventoji Port was marked on maps, and from the 16th to the 18th centuries, it was visited by English, Dutch, and Swedish ships. These ships exported grains, furs, honey, and imported iron, manufactured goods, salt, wine, silk, and weapons. English merchants were granted the privilege to establish a port where large merchant ships could enter.
In 1589, by the resolution of the Parliament of the Polish-Lithuanian Commonwealth, Šventoji Port was expanded. Foreign ships visited this port particularly intensively during the reigns of Vladislovas Vaza (1632–1648) and Jonas Kazimieras (1648–1668), especially when in 1655, Charles X Gustav occupied not only the coastal areas of Lithuania but also the entire Western Lithuania. During that time, Šventoji Port became a serious competitor to the ports of Klaipėda and Königsberg.
In 1639, influenced by Klaipėda merchants, Vladislovas Vaza issued an order through the Margrave of Brandenburg, Elector George William, against those who sent goods from the Lithuanian coast through Gdańsk instead of Klaipėda, thus cutting off revenues to the king’s treasury (the king received a 2% duty on the value of goods) and to the city of Klaipėda, which was impoverished due to the war. The Samogitians also noticed the intense trade through Šventoji. In 1639, the Samogitians burned the English trading office in Šventoji Port, as well as ships, warehouses, and workshops.