The exploitation of wind energy worldwide comprises one of the main factors for reaching the targets towards a non-fossil fuel era set by many countries. Nowadays, onshore wind power is an established industry with significant contribution to energy production. On the other hand, offshore wind power is an emerging industry where numerous challenges should be faced. Apart from the main components such as platforms, turbines, cables, and substations, offshore installations include also the manufacturing, construction, shipping, and decommissioning phases. Additionally, the Operation & Maintenance (O&M) activities consist of employees’ transportation by vessel or helicopter and occasional hardware retrofits. Therefore, various life cycle (LC) stages of offshore projects present a carbon footprint which affects their sustainable character in a more significant way than onshore ones. Concerning the environmental uncertainties arisen from the greenhouse gas (GHG) emissions of offshore wind power generation, the present work intents to provide a literature review on the LC carbon and energy footprint of offshore wind power projects compared to the onshore counterparts.