Long-range acoustic communication is crucial to underwater applications such as collection of scientific data from benthic stations, ocean geology, and remote control of off-shore industrial activities. However, the transmission rate of acoustic communication is always limited by the narrow-frequency bandwidth of the acoustic waves because of the large attenuation for high-frequency sound in water. Here, we demonstrate a high-throughput communication approach using the orbital angular momentum (OAM) of acoustic vortex beams with one order enhancement of the data transmission rate at a single frequency. The topological charges of OAM provide intrinsically orthogonal channels, offering a unique ability to multiplex data transmission within a single acoustic beam generated by a transducer array, drastically increasing the information channels and capacity of acoustic communication. A high spectral efficiency of 8.0 ± 0.4 (bit/s)/Hz in acoustic communication has been achieved using topological charges between −4 and +4 without applying other communication modulation techniques. Such OAM is a completely independent degree of freedom which can be readily integrated with other state-of-the-art communication modulation techniques like quadrature amplitude modulation (QAM) and phaseshift keying (PSK). Information multiplexing through OAM opens a dimension for acoustic communication, providing a data transmission rate that is critical for underwater applications.high-speed acoustic communication | high spectral efficiency | orbital angular momentum | multiplexing | demultiplexing W ith the increasing amount of human activities underwater including unmanned vehicle exploration, off-shore industrial applications, and remote ocean environment monitoring, the development of underwater communication has become essential. The intrinsic strong absorption of microwave and mid-and far-infrared radiations by water molecules limits the propagation distance of radio frequencies to mere centimeters (1-4), making rf wireless communication approaches impossible. On the other hand, optical waves are scattered by objects in the ocean such as small particles, debris, and marine life due to the shorter wavelengths, limiting the range of optical communication underwater to be within just 200 m (5-7). Presently, acoustic waves are the only option for long-range (over 200 m) underwater communications. However, the applicable bandwidth of acoustic waves is limited within 20 kHz because the higher damping loss of high-frequency acoustic waves in water reduces the propagation distance to less than a kilometer range (8). Such a low carrier frequency limits drastically the spectral bandwidth and data rate accessible for data transmission. Although spectral efficiency has been improved through recent advanced communication technologies such as differential phase-shift keying (PSK) and quadrature amplitude modulation (QAM), the number of available data transmission channels remains tied to the low carrier frequency (9-13).We propose to overcome such ...