The goal of this thesis was to propose a new design for a kitefoiling harness for the Dutch Olympic team, which does not cause major discomfort, stays in the same location on the body and properly supports the body of the athlete. In the discovery phase, three main problems with existing harnesses were found. First, as the harness is pulled up the body while kitefoiling, the legstraps put an uncomfortably large amount of pressure on the groin. Second, ideally the attachment point between the harness and the kite sits around the crotch, but as the harness is pulled up the attachment point moves as well. Furthermore, the attachment point moves around too much in general. Last, the shape of the harness does not always fit the athlete well, causing weird pressure points, which are perceived as uncomfortable. Two extreme postures were identified that harnesses need to perform well in: going upwind and doing a manoeuvre. Through force analysis it was found the highest forces that the harness has to endure are in the upwind posture. Major shear forces should be avoided. The athletes prefer to be supported most at the Gluteus Maximus and the lower back. The design approach for this project was prototype focussed, with every design stage being tested and validated. First, general concept directions were designed and evaluated. This evaluation led to two major pain points in the design: too much pressure on the hips and too much pressure at the groin. Two subsequent design sprints were then completed to solve these two pain points. The outcomes were tested with members of the Dutch Olympic team. The final proposed design is radically different than existing kitefoiling harnesses on the market. The new design removes the spreaderbar and makes the attachment point much smaller. Additionally, it contains much bigger legstraps that keep the entire harness in place and are connected to a hard belt that is custom moulded to the shape of the back of the athlete. Apart from the hard belt, everything can be adjusted to ensure the best possible fit. During final testing it was found that, overall, the new design does not perform better than the current best harness on the market. The freedom of movement is greatly reduced and the leg straps were perceived as very uncomfortable, partly due to a much higher pressure from the kite in manoeuvres than anticipated. The newly designed leg straps did stay in place perfectly and kept the attachment point in the same place. Ultimately, the design should be tested with more participants. Even though the design is currently not better than the compared harness, some suggested adjustments could have a positive impact on the discomfort that the athlete perceived.