A coupling device for connecting a first fluid line to a second fluid line may include a first connecting piece having a first outer latching contour on its outside and may be connected to at least one of the first fluid line and the first outer latching contour. The coupling device may also include a second connecting piece having a second outer latching contour on its outside and being connected to at least one of the second fluid line and the second outer latching contour. A sleeve may also be provided in which both connecting pieces may be inserted on opposite ends thereof. The sleeve may have inner latching contours on its inner side, the inner latching contours being complementary to the outer latching contours and latching with the outer latching contours when the connecting pieces are inserted. The sleeve may be enclosed by a protective cover.