Abstract: Integrated communication and localization (ICAL), owing to its advantages in channel resource utilization and hardware integration, is highly suitable for resource-constrained underwater acoustic applications and attracts extensive research attention in recent years. This paper first addresses the core technologies, with a particular focus on the orthogonal frequency-division multiplexing (OFDM) configuration, and then analyzes the issues of integrated waveform design, channel modeling, and receiver signal processing. Subsequently, the research progress related to three representative application scenarios, i.e., portable deployment, underwater wireless sensor networks, and submersible clusters, is reviewed and summarized. Finally, regarding existing limitations and further deployment of underwater acoustic ICAL, possible technical challenges and potential research directions are outlined from the perspectives of signal design, channel modeling, application scenarios, and performance analysis.