A plug-in coupling for connecting a fluid conduit to a pipe has a pipe section having a first end section to be connected to a fluid-conduit and a second end section to receive and lock a pipe. A securing ring is attached to the inner side of the pipe section. At least one sealing ring is inserted into the pipe section and seals the pipe relative to the pipe section. The at least one sealing ring is positionally secured in the pipe section between the securing ring and an inner shoulder of the pipe section. The pipe section has a slot extending in a circumferential direction of the pipe section and a support surface located opposite the slot. The securing ring is inserted into the slot until the securing ring contacts the support surface. A circumferential section of the securing ring is received in the slot.