Open access (OA) to scientific information is one of the major challenges and objectives of actual public research policy. The purpose of this paper is to assess the degree of openness of scientific articles on bioeconomy, as one of the emergent research fields at the crossroads of several disciplines and with high societal and industrial impact. Based on a Web of Science (WoS) corpus of 2489 articles published between 2015 and 2019, we calculated bibliometric indicators, explored the openness of each article and assessed the share of journals, countries and research areas of these articles. The results show a sharp increase and diversification of articles in the field of bioeconomy, with a beginning long tail distribution. 45.6% of the articles are freely available and the share of OA articles is steadily increasing, from 31% in 2015 to 52% in 2019. Gold is the most important variant of OA. Open access is low in the applied research areas of chemical, agricultural and environmental engineering but higher in the domains of energy and fuels, forestry and green and sustainable science and technology. The UK and the Netherlands have the highest rates of OA articles, followed by Spain and Germany. The funding rate of OA articles is higher than of non-OA articles. This is the first bibliometric study on open access to articles on bioeconomy. The results can be useful for the further development of OA editorial and funding criteria in the field of bioeconomy.