Disclosed are various embodiments for customer-defined capacity limit plans in communication networks. In one embodiment, a request for a service from a radio-based network is received from a first client device. A network function in the radio-based network is determined to be at a capacity limit. Service from the network function to a second client device to the network function is suspended in response to determining that the network function in the radio-based network is at the capacity limit and based at least in part on a rule set specific to the radio-based network. The first client device is provided access to the network function instead of the second client device.