Living labs provide a new, under researched form of open innovation. Although open innovation is increasingly popular in service development, extant literature lacks knowledge of different open service innovation strategies, which companies can employ. This chapterfocuses on strategies that firms can take in co-creating service innovations through living labs. The authors found nine open service innovation strategies based on an analysis of 26 living labs in four countries. Understanding of strategies and their links with incremental or radical innovation outcomes aid managers to set up an efficient innovation management. Knowledge of various strategies helps companies to succeed in service development and innovation novelty assessment based on the characteristics of the living lab.