In embodiments of mesh network commissioning, a commissioning device establishes a secure commissioning communication session between the commissioning device and a border router of a mesh network to securely establish network communication sessions for joining one or more joining devices to the mesh network. The commissioning device can activate joining for the mesh network, and receive a request from a joining device to join the mesh network. The commissioning device can establish a secure joiner communication session between the commissioning device and the joining device, authenticate the joining device using an encrypted device identifier, and join the joining device to the mesh network.