Swimming is a sport that poses particular challenges for manufacturers of knitted fabrics. Swimwear, caps, swimming suits made of fabrics are exposed to considerable mechanical stress. They are exposed to direct contact with water, which is often chlorinated or ozoned, creating a risk of loss of mechanical properties as a result of chemical reactions. After the swimming clothing is wet for a long time, there is a risk of microorganisms growth. Sport costumes are also used in a wide range of temperatures. Beyond being used in the swimming pool, they are often taken to the sauna and exposed to the sun. Variable temperature and ultraviolet light can change the structure of the fabric, if it is not properly prepared for such hostile environment. Growing concern for ecology imposes the need for low-energy manufacturing and recycling processes. In effect production of good fabric becomes a challenge. First of all it is necessary to use the highest quality materials and meticulous observance of quality control at every stage of production.