In medieval times, Trelleborg had an important part in herring fishing. At that time, this was conducted along the entire coast line of what is now Sweden, as the herring shoals were of such great numbers that fishermen were said to have been able to stand on the shore and land fish with nets. Trelleborg became an important merchant city as merchants from Germany came to trade herring. In 1619 following a devastating fire, the Danish King decided that one merchant city on the coast was sufficient and revoked Trelleborg's status as a merchant city in order to favour Malmö.
Not until 1840 was Trelleborg allowed to become a merchant city, and not until 1867 it regained its rights as a city of Sweden. Mostly this was thanks to the work of a few stubborn men, who had continuously been petitioning the Swedish Riksdag with these requests since 1658. The local government reform of 1971 made Trelleborg the seat of Trelleborg Municipality, covering both rural and urban areas.
It is today often visited by people travelling from Sweden to Germany because of the ferries to Rostock, Sassnitz and Lübeck - Travemünde in Germany. These ferries began sailing on May 1, 1897 with the Sassnitz line; the route to Travemünde was established in 1962, while the line to the former East German city Rostock was inaugurated after the fall of the Berlin Wall in 1989. The ferries carry both passengers on one-day journeys, cars with vacationing families, and heavy trucks on their way through Europe. In April 1917, Lenin arrived with the ferry from Sassnitz to Trelleborg on his way from exile back to Russia to lead the Revolution.
Overlooking the harbour of Smygehuk near Trelleborg is a statue of a nude woman that was installed in 1930. Uma Thurman's grandmother, the mother of Nena von Schlebrügge, was the model for this statue.