The present invention relates to a catheter, especially an expandable catheter with a transition between the individual sections allowing insertion of the transition into urethra. In particular the present invention relates to a catheter which is operable between a collapsed configuration for storage and transportation and an expanded configuration for draining fluid from a body via a conduit which extends axially in a longitudinal direction from a proximal end to an opposite distal end, the catheter comprising: a proximal section, adapted to be fully inserted into a urinary channel of the body and forming a proximal part of the conduit which part extends axially between the proximal end and a first transition end of the proximal section, and a distal section, adapted to be at least partially inserted into the urinary channel and forming a distal part of the conduit which part extends axially between a second transition end of the distal section and the distal end, an insertable part of the first transition end being dimensioned to enable its positioning inside a receiving portion of the distal part of the conduit to enable axial movement of the sections relative to each other to operate the catheter between the collapsed configuration and the expanded configuration of the catheter, wherein the sections comprise cooperating coupling structures to support the catheter in the expanded configuration.
