This manual describes “best practices” for acquiring ocean-velocity data using Lowered Acoustic Doppler Current Profiler (LADCP) systems. Adherence to the recommendations in this manual should help ensure that the acquired data can be processed to derive full-depth absolute velocity profiles of high quality. Processing LADCP data, which is not covered in this manual, is not a trivial task and there are several publicly available software packages available for this purpose. Care has been taken to ensure that the guidelines in this manual are independent of the processing software. In principle, any ADCP instrument with sufficient depth rating can be lowered on a wire to obtain LADCP data.