A garment, such as an article of aquatic sportswear, that includes a torso-forming portion having a front surface and a rear surface, and which is provided with openings for the passage of the head, legs, and arms. The garment includes an opening in the form of a slit provided with a fastening mechanism, such as a slide fastener, for selectively opening and closing the slit. The slit and the slide fastener includes an essentially rectilinear main portion which extends into a curved end portion.