Floating offshore wind is a relatively nascent technology which overcomes the current techno-economic depth restrictions imposed by bottom-fixed substructures. Due to this great potential, floating offshore wind will soon enter the commercial deployment phase. With a full pipeline of projects towards Final Investment Decision (FID) until 2030 and the set out goals for 2050 the reduction of its Levelized Cost of Energy (LCOE) is a key target. Increasing its energy density, always granting technology feasibility and reliability while seeking a minimal environmental impact is an important aspect which can be achieved by new component designs, upscaled wind farms, thorough and multi-disciplinary development and optimised maintenance strategies resulting in cost-efficient Floating Energy Systems Integration (FESI). This chapter introduces and assesses the latest floating wind technologies, the optimised integration of multiple turbines in FOWFs, network integration recommendations and control strategies. Additionally, the main concepts related to the development, Transport and Installation (T&I), Operation and Maintenance (O&M) and decommissioning stages necessary to achieve a favourable cost balance and a sustainable technology deployment are described. Finally, the combination of floating wind power with other energy sources such as wave energy and energy storage systems (e.g., offshore hydrogen) are introduced as modern alternatives to achieve integrated floating offshore wind energy systems. These innovations lead towards cost-efficient Offshore Multi-Energy Systems (OMES) that take advantage of shared exploitation areas and infrastructure.