This document provides recommendations for the sizing, specification, system integration, and testing of subsea flow meters [referred to as multiphase flow meters (MPFMs)] for measurement of full stream, multiphase flow. In subsea applications, MPFMs are normally used in well testing, allocation measurement, fiscal measurement, well management, and/or in flow assurance applications. The categorization of MPFM application is important since it can be used to determine the required level of factory testing, independent verification, field maintenance, and ongoing verification required during operation. This Recommended Practice (RP) includes wet gas flow meters as a subset of MPFMs. In-line MPFMs are typically used in subsea applications and are the focus of this RP. These recommendations and guidelines are intended for use by the engineer responsible for the delivery of the MPFM.