The rise in tourism arrivals and the need for the achievement of sustainability goals have also caused an ever-growing attention towards sustainable tourism. Recently, online platforms and tour operators have become one of the most common means of booking in tourism and they can play an important role for the promotion of sustainable tourism. The objective of this paper is to identify to what extent and how the concept of sustainability can be integrated within these websites and whether this has already been done. Additionally, a set of life-cycled-based indicators is aimed to be identified or proposed for the selection of sustainable accommodation within these websites. Tourists would therefore be assisted when it comes to choosing the most sustainable option of accommodation, in the same way as they can already do today when selecting the most convenient fare or the most suitable location and features.