This paper presents an innovative joining process for the longstanding challenge of connecting two tubes by their ends at room temperature by means of a simple, effective and environmental friendly solution. The process is performed in one stroke and makes use of tube expansion to put the mating surfaces of the two tubes in a correct position for subsequent locking by means of plastic instability and simultaneous compression beading.The presentation combines experimentation with commercial S460MC (carbon steel) welded tubes and finite element modelling with the purpose of characterizing the deformation mechanics of the process, identifying its major operating parameters and providing basic design guidelines to successfully perform the end-to-end joining of tubes by plastic instability. The new proposed joining process has potential to easily and efficiently replace existing solutions based on the utilization of fastened, crimped, welded, brazed or adhesive joints.