A Vorpostenboot (plural Vorpostenboote) was an auxiliary warship used by Germany in both World Wars. Many vorpostenboote also served in other roles, such as sperrbrecher (mine clearance) and weather ships. During World War II, the Vorpostenboote were organized into several surface flotillas which were in turn attached to various German ports. Over 30 Vorpostenflotillas were established to operate off the German, Channel, Baltic and Scandinavian coasts.