The utility and cost-effectiveness of instrumentnetworks are enhanced by instrument interoperability. Today’soceanographic instruments are characterized by very diversenon-standard software protocols and data formats. This diversityof protocols poses serious challenges to integration of large-scalesensor networks. Standard instrument protocols are now beingdeveloped to address these challenges. Some of these standardsapply at the IP-network level and enable integration of existing“lower level” proprietary instrument protocols and softwarecomponents. Other approaches are intended to be implementedby the instrument device itself. These native instrument protocolstandards offer the possibility of more uniform and simplersystem architectures. We compare these various approaches,describe how they can be combined with one another, anddescribe some prototypes that implement them.