These are the traditional "Speedo" style swimming briefs. Often (confusingly) referred to as swimming trunks. This style was prevalent in the late 20th and early 21st century in UK pools and is still
incredibly popular with our European cousins. Swim briefs feature a high-cut rounded leg as opposed to the lower, more square legs of the swim trunks. Many professional swimmers and divers prefer
swim briefs over any other form of men's swimwear due to their low resistance in the water and simple design.