Methods, systems, apparatuses, and computer program products for providing an enforcement mechanism for the maximum number of PDU sessions per network slice in a communication system are provided. A method, system, and apparatus may receive, from a user equipment (UE), a protocol data unit (PDU) session establishment request message and Single Network Slice Selection Assistance Information (S-NSSAI) through an access network (AN). The method, system, and apparatus may cause, upon detecting that the S-NSSAI is subject to the capping number of PDU sessions per network slice, transmission of a service request message to a network slice selection function (NSSF). The service request message includes an indication indicating that the S-NSSAI is subject to a capping number of PDU sessions per network slice. The indication may cause the NSSF to increment a counter associated with PDU sessions for a network slice associated with the S-NSSAI.