After years of criticism for lacking clear guidance on how environmental or sustainability cooperation agreements would be assessed for competition law compliance, the European Commission has introduced a new Chapter 9 in the revised EU Horizontal Guidelines. Similarly, the UK has adopted its own guidance for environmental sustainability agreements. Explored in this article are (i) the types of sustainability agreements that are unlikely to breach EU and UK competition rules, (ii) the soft safe harbour for sustainability standardisation agreements, and (iii) how consumer non-monetary benefits are considered to balance out competition concerns in sustainability agreements.