Method for providing a roaming functionality related to an Internet Protocol Multimedia Subsystem session, wherein a first User Equipment (UE A) is associated to a Home Public Land Mobile Network (HPLMN) and wherein the first User Equipment (UE A) roams in a Visited Public Land Mobile Network (VPLMN), wherein the Home Public Land Mobile Network (HPLMN) comprises a first Internet Protocol Multimedia Subsystem domain, wherein the Visited Public Land Mobile Network (VPLMN) comprises a second Internet Protocol Multimedia Subsystem domain, and wherein the Visited Public Land Mobile Network (VPLMN) comprises a Roaming Border Control Function (RBCF), wherein a session set-up of an Internet Protocol Multimedia Subsystem session requires the handling of control signaling and the establishment of a user plane path, wherein in case of a session set-up request originating from the roaming first User Equipment (UE A) (mobile originating case) towards a second User Equipment (UE B), the second User Equipment (UE B) being attached to a target network, the method comprises the steps of: -- the second Internet Protocol Multimedia Subsystem domain transmitting a session set-up request control signaling to the first Internet Protocol Multimedia Subsystem domain, -- the first Internet Protocol Multimedia Subsystem domain transmitting the session set-up request control signaling in forward direction to the Roaming Border Control Function (RBCF) of the second Internet Protocol Multimedia Subsystem domain, and wherein the second Internet Protocol Multimedia Subsystem domain is used to handle the user plane path and the associated control signaling to terminate the session set-up, whereby, since local break out of the media shall be applied for the roaming first User Equipment (UE A), the Roaming Border Control Function (RBCF) provides a linking of -- the signaling received via a loop through the first Internet Protocol Multimedia Subsystem domain in the Home Public Land Mobile Network (HPLMN) -- with the media anchored due to the local break out in the second Internet Protocol Multimedia Subsystem domain in the Visited Public Land Mobile Network (VPLMN). -- the second Internet Protocol Multimedia Subsystem domain transmitting a session set-up request control signaling to the first Internet Protocol Multimedia Subsystem domain, -- the first Internet Protocol Multimedia Subsystem domain transmitting the session set-up request control signaling in forward direction to the Roaming Border Control Function (RBCF) of the second Internet Protocol Multimedia Subsystem domain, and wherein the second Internet Protocol Multimedia Subsystem domain is used to handle the user plane path and the associated control signaling to terminate the session set-up, whereby, since local break out of the media shall be applied for the roaming first User Equipment (UE A), the Roaming Border Control Function (RBCF) provides a linking of -- the signaling received via a loop through the first Internet Protocol Multimedia Subsystem domain in the Home Public Land Mobile Network (HPLMN) -- with the media anchored due to the local break out in the second Internet Protocol Multimedia Subsystem domain in the Visited Public Land Mobile Network (VPLMN).