Dolphin is a pioneering system designed to facilitate access to lightweight internet applications (such as email, tweets, and news snippets) during shutdowns by leveraging the cellular voice channel to transmit data bits encoded into audio during a voice call. Recognizing that cellular services often remain operational during shutdowns, users within affected regions require peers outside the region to send and retrieve content on their behalf. Dolphin overcomes challenges such as bandwidth limitations, unreliability, and eavesdropping, prioritizing usability for regular users with basic devices. This innovative solution has undergone successful testing during actual internet shutdowns, proving its effectiveness in accessing essential online content. Both laboratory and real-world tests have confirmed Dolphin’s ability to provide internet access during critical situations.