The disclosed systems and methods authenticate a user of a telecommunications network for a third-party service provider to seamlessly provision a third-party service. A The telecommunications network receives an indication that a user device on the telecommunications network received an input by a user to access the third-party service. In response, the telecommunications network obtains a network-based identifier (e.g., IP address) that uniquely identifies the user device and associated user, determine that the user is eligible for the third-party service based on the user's subscribed service plan, and communicates information to enable the third-party service provider to automatically provision the third-party service on the user device without needing additional input to activate the third-party service or authenticate the user with the third-party service on the user device.