A system is provided for supporting roaming between LTE EPC network and 5G network of a first mobile network operator by 5GC network of a second network operator. The system may include the EPC network including a serving gateway in communication with a 4G base station being in the EPC network. The system may also include the 5G network of the first mobile network operator including a vSMF in communication with a 5G base station being in the 5G network of the first network operator. The system may also include the 5GC network of the second network operator including a hSMF. The vSMF is configured to receive a communication from the serving gateway to anchor mobility between the LTE EPC network and the 5G network of the first mobile network operator, and to communicate with the hSMF in the 5GC network of the second network operator using 5G roaming interfaces.