Where can I publish a book open access without (necessarily) paying a fee? A list of Diamond open access options

"It is important to note that there is virtually no 100% Diamond open access press – always contact a press you are interested in early on to discuss this option. Please note also that even many fully Diamond OA presses would prefer to receive a BPC if one is available to you at your institution, to help them to focus their support on authors who are unaffiliated or who do not have access to institutional funds such as many early career researchers....

These models are often referred to as ‘Diamond’ open access, to differentiate it from open access models in which fees are paid by authors. While there have been some recent moves, such as by the Diamond Discovery Hub, to change the definition of Diamond to exclude some publisher types, this list does not make this distinction and includes publishers of all type and size.  

It has been collated from my own knowledge gained during my time on the Copim Project, working on the Opening the Future Diamond OA funding model, and relies on details from public-facing publisher and funding scheme websites. It has been partially supplemented by the addition of a small number of European Diamond OA publishers from the Diamond Open Access Book Publishers List published in September 2025 by Lena Ryzhová and Benedetta Siviero of the Diamond OA Expertise Center."