Kollam district had been a main centre for trade since the olden times. As it had a sea port, trade relations with many foreign countries including Chinese, Romans etc were prominent. There was a period which saw vast settlements of Chinese due to the exchange of embassies between the rulers of Kollam and China. In the 9th century, Kollam was the only port in India that had connections with the Chinese. Marco Polo who was a Venetian traveler visited Kollam in 1275.
In 1502, Portuguese started trade with Kollam. After them the Dutch came in 1795. According to the treaty signed by the British with the Travancore, a military post of the British was established at Kollam. A main personality who struggled for the development of Kollam town was Velu Thampi Dalawa. Merchants and traders from Chennai were invited by him to stay in Kollam. The rulers of Desinganad made Kollam as their capital.
In 1835, the Travancore has 2 revenue divisions namely Kollam and Kottayam. When Travancore and Cochin were integrated in 1949, Kollam remained as one of the revenue divisions of the state. After which it was made a district.