Embodiments of this application provide a method for an application to access a network, an apparatus, and a system. The method includes: receiving a first message from an application instance access module, the first message is used to request to establish a first connection for a first application instance; sending a second message to the first user plane function entity, the first user plane function entity serving the first application instance; the second message includes identification information of the first application instance; receiving a third message from the first user plane function entity, the third message includes an establishment result of the first connection; and when the establishment result is a success, sending a fourth message to the application instance access module, the fourth message includes a first address allocated by a core network element to the first connection.