Introduction
Plan S set out in 2018 to make publicly funded research free to read the moment it is published. Eight years on, it has changed how publishers price and license research, but cOAlition S is now rethinking how it gets there. This article looks at where Plan S came from, what it requires, what it has achieved, and what its new strategy for 2026 to 2030 means.
Key points
- Plan S was launched in September 2018 by 11 national research funders, with the backing of the European Commission and the European Research Council. Wellcome and the Gates Foundation joined soon after.
- It requires immediate open access under a CC BY license through one of three routes: a fully open access journal or platform, a transformative arrangement, or a repository deposit with zero embargo.
- The Rights Retention Strategy lets funded authors share their accepted manuscripts immediately, even when they publish in subscription journals.
- cOAlition S members stopped paying for publishing under transformative arrangements after 2024.
- Its Strategy 2026–2030, published in November 2025, shifts the emphasis toward diamond open access, preprints, and publish-review-curate models.
Plan S is run by cOAlition S, a group of research funders that now numbers 28 organizations in Europe, North America, Africa, the Middle East, and Australia. It requires research funded by its members to be published in compliant open access journals or platforms, or made openly available in repositories without embargo. The original start date of 2020 was pushed back to 2021 after consultation.
At first glance, Plan S sounds like the proverbial white knight, galloping in to rescue academia from the iron grip of paywalls and sky-high subscription fees. Its promise is simple yet powerful: immediate, free, unrestricted access to research outputs paid for by the public. However, beneath this glossy promise lies a complex web of challenges, resistance, unintended consequences, and fundamental questions about the future of scholarly publishing.
This article delves deeply into Plan S—its origins, goals, implementation struggles, industry impact, and the debates surrounding its future—to assess if it truly is the champion open access needs or just another idealistic reform oversimplifying a multifaceted problem.
The Genesis of Plan S: A Response to the Open Access Impasse
The traditional academic publishing model has long been built around subscription fees paid by libraries and institutions. This system, developed in a print era, has faced mounting criticism as digital technology has rendered physical distribution costs negligible. Despite that, countless research articles remain locked behind paywalls, inaccessible to many who would benefit from their knowledge.
Open access advocates have been pushing back for decades, seeking to make scientific knowledge free at the point of access. Various models emerged, including green OA (self-archiving in repositories) and gold OA (publishing in fully open journals). Yet, progress was slow and patchy. Publishers held tight to profitable subscription models, while researchers struggled to balance prestige, impact factors, and mandates from funders.
Plan S was born in this context. It was developed by Robert-Jan Smits, the European Commission’s open access envoy, with Science Europe, and launched in September 2018 by 11 national funders, among them UK Research and Innovation, the Research Council of Norway, and the Dutch Research Council (NWO). Wellcome and the Bill & Melinda Gates Foundation joined soon after.
The premise was straightforward: publicly funded research must be openly accessible immediately upon publication. This was not a polite suggestion but a mandate, which came into force in 2021. We look at how it has played out in Europe in Plan S and Academic Publishing in Europe and explain the principles in Demystifying Plan S.
What distinguished Plan S from previous policies was its uncompromising nature. Hybrid journals—those publishing a mix of subscription and OA articles—would not be compliant unless transitioning to full OA models. Furthermore, Plan S championed the use of liberal Creative Commons licenses, specifically CC BY, to ensure wide reuse and redistribution rights.
Financially, Plan S introduced a major shift by supporting Article Processing Charges (APCs) to cover publishing costs. Instead of libraries paying subscriptions, authors or their funders would pay APCs upfront. The assumption was that this would incentivize publishers to convert fully to open access, thus dismantling paywalls and accelerating knowledge flow.
The Promises of Plan S: Revolution or Evolution?
Plan S brought a suite of promises that ignited enthusiasm across many corners of academia. For open access proponents, it was a breath of fresh air: an assertive step toward transparency, democratization of knowledge, and faster scientific progress. The logic was compelling: research funded by public money should be accessible to all without barriers.
From an academic perspective, Plan S aimed to remove paywalls that hinder visibility, citation, and interdisciplinary collaboration. If research were freely available, it could be accessed by scientists in developing countries, policymakers crafting legislation, educators preparing lessons, and entrepreneurs innovating products.
By advocating for clear licensing under Creative Commons, Plan S further pushed for innovation beyond academia. Businesses and NGOs could legally reuse and build upon research, expanding its impact exponentially. The approach aligned with broader open science ideals promoting transparency, reproducibility, and societal engagement.
On the publishing front, Plan S sought to spur a major shift from legacy subscription journals to sustainable, transparent OA business models. Transformative agreements, where subscription revenue is repurposed into OA fees, were seen as a transitional tool to achieve full open access ecosystems.
That transition had a deadline.
In January 2023, cOAlition S confirmed that its members would stop paying for open access publishing under transformative arrangements, including transformative journals, after 2024. Whether those deals delivered real change is another matter, as we look at different perspectives about transformative agreements.
Plan S’s strict deadlines and compliance criteria sent a strong message: incremental change was no longer acceptable. The plan aimed to accelerate a revolution in scholarly communication, sparking publishers to innovate or risk becoming obsolete.
The Three Routes to Compliance
For all its strictness, Plan S does not force a single publishing model. It offers three ways to comply, each with immediate access and a CC BY license.
The first is to publish in a fully open access journal or platform, such as one listed in the Directory of Open Access Journals (DOAJ). The second is to publish in a subscription journal covered by a transformative arrangement, such as a read-and-publish deal in which one institutional fee covers both reading and open access publishing. These arrangements were meant to be temporary, and funder support for them ended after 2024.
The third route is the repository. Authors can publish in a subscription journal as long as they deposit their accepted manuscript in an open repository with no embargo and under a CC BY license. To make this possible, cOAlition S funders ask grant holders to apply the license to the manuscript at submission. This Rights Retention Strategy overrides later publisher agreements that would otherwise impose an embargo, so the research is open immediately even if the published version sits behind a paywall.
The Reality Check: Implementation Challenges and Industry Pushback
Despite its lofty ideals, Plan S’s rollout has met fierce pushback and practical obstacles. The academic publishing landscape is deeply entrenched, with complex incentive structures, financial dependencies, and cultural norms. Attempting rapid, sweeping change has proven akin to trying to turn an ocean liner on a dime.
First, the compliance requirements posed difficulties for many researchers. Not all disciplines or regions have sufficiently developed OA journals or platforms that meet Plan S standards. This is particularly true in the humanities and social sciences, where OA infrastructure lags STEM fields. Researchers found themselves stuck between funder mandates and limited publishing options.
Second, hybrid journals remain the dominant publishing model in many disciplines, and major publishers resisted Plan S’s categorical rejection of them. Publishers argued that the plan ignores the realities of the scholarly ecosystem and risks fragmenting it. Critics pointed out that the APC funding mechanism may simply shift paywalls from readers to authors, raising equity concerns. Researchers or institutions with less funding could be effectively priced out of publishing.
Hybrid journals were a target for a reason. Publishers could charge an article processing charge for open access while still collecting subscriptions for the same journal, a practice known as double-dipping. But many smaller society publishers relied on hybrid income to fund meetings, training, and advocacy. Losing it pushed some to sell or license their journals to larger commercial publishers, which risked strengthening the very players Plan S set out to challenge.
Licensing caused friction too. Some researchers in the humanities and social sciences consider CC BY too permissive and would prefer more restrictive licenses such as CC BY-NC or CC BY-ND to limit commercial reuse of their work.
Third, Plan S raised thorny issues around academic freedom and career progression. Researchers worried about mandates dictating where they can publish, potentially limiting choices or forcing them away from prestigious journals crucial for tenure and promotion. This dynamic created tension between open access goals and individual career incentives.
Fourth, Plan S’s initial focus on European funders and journals caused friction with the global research community. Many funders outside Europe hesitated to adopt similar mandates, creating a fragmented system. Cross-border collaborations faced complications as compliance rules diverged. The coalition has since grown beyond Europe, but most of its members are still European funders.
Finally, critics worried that pressure to publish open access could push some authors toward questionable journals with weak peer review. Plan S’s reliance on recognized journals and platforms was meant to guard against this, but the wider growth of predatory publishing has kept the concern alive.
How Plan S Has Influenced the Publishing Ecosystem
Despite challenges, Plan S has undeniably shaken the scholarly publishing world. It turbocharged discussions around open access and pressured publishers to innovate rapidly. Several publishers responded with transformative agreements, new OA journal launches, and more transparent APC pricing.
Show the data as a table
| Share of articles | 2015 | 2025 |
|---|---|---|
| Gold open access (including hybrid) | 17% | 44% |
| Other free versions (green and bronze) | 17% | 6% |
| Subscription only | 66% | 50% |
Plan S also pushed for price transparency. It expects article processing charges to reflect the services publishers actually provide, and cOAlition S backed a Journal Comparison Service so that funders and libraries can see what publishers charge and what they deliver for the money.
Plan S also drew attention to alternative OA business models beyond the APC system. For example, “diamond open access” journals charge no fees to authors or readers, relying instead on institutional or governmental support. This is gaining traction as a sustainable and equitable option. cOAlition S has supported this route through the 2022 Action Plan for Diamond Open Access and European projects such as DIAMAS. We look at how these journals are supported in a discussion about open access funding.
Libraries and research institutions have shifted budgets to support APC payments and compliance services. They have also embraced preprint servers and institutional repositories to maximize accessibility.
Nevertheless, unintended consequences surfaced. The emphasis on Plan S-compliant journals has sidelined important subscription journals with regional or niche significance. In some cases, researchers’ publishing options are narrowed, especially in smaller fields.
The initiative also exposed disparities between well-resourced and less-resourced institutions. Larger universities can navigate APCs and compliance with relative ease, while smaller or developing-country institutions struggle, raising serious equity questions.
Plan S and the Role of Technology: A Double-Edged Sword
Technology plays a pivotal role in Plan S’s vision, but it also reveals new challenges. Digital platforms enable rapid, free dissemination of research, but infrastructure gaps remain.
Plan S encourages the use of open repositories and preprint servers, which proved invaluable during urgent situations like the COVID-19 pandemic. These tools accelerate knowledge sharing beyond traditional publication cycles.
At the same time, repositories face issues with a lack of standardization, version control, and quality assurance. This can lead to duplicated efforts, confusion over the most authoritative version, or dissemination of unvetted information.
Artificial intelligence and automation are being deployed to ease administrative burdens, such as compliance checks and metadata management. However, these technologies require investment and expertise, creating potential barriers for smaller institutions or publishers.
Technological innovation also sparks debates about the future role of publishers. As dissemination tools proliferate, publishers must justify their value beyond distribution through quality assurance, curation, and community-building.
The Global Perspective: Inclusivity and Equity Concerns
Plan S’s principles resonate globally, but its APC-centric approach has raised concerns about widening inequalities. The promise of open access is universal, yet implementation risks marginalizing researchers in developing countries or underfunded disciplines.
Critics warn that the current OA funding model privileges wealthy institutions able to cover APCs, leaving others behind. Language bias also persists, as many OA journals publish primarily in English, limiting participation from non-English-speaking researchers.
Plan S has sparked broader debates about how to build a truly global, inclusive scholarly communication system. Models like diamond OA and regional consortia gain attention as ways to ensure equitable participation.
There are also discussions about the digital divide, where access to infrastructure and internet connectivity remains uneven worldwide, affecting who can benefit from open access resources.
The Future of Plan S: Evolution or Revolution?
The question remains: Is Plan S the white knight poised to rescue open access publishing, or is it an idealistic initiative with flaws that need serious revision?
Plan S is neither a flawless savior nor a doomed failure. It acts as a catalyst, forcing a reckoning with long-standing publishing problems. Its strict mandates revealed weaknesses and inequities but also spurred innovation and dialogue.
That evolution is already under way.
In November 2025, cOAlition S published its Strategy 2026–2030. Following a consultation on its “Towards Responsible Publishing” proposal, it commits to reviewing the Plan S principles with more emphasis on diamond open access, preprints, and publish-review-curate models, and to developing a common position on AI, including whether CC BY content can be used to train AI models. Individual funders are moving in the same direction. Since January 2025, the Gates Foundation no longer pays article processing charges and instead requires grantees to share preprints.
The scholarly publishing landscape is too complex for a one-size-fits-all solution. Cultural change, technological investment, and realignment of incentives will be essential. Plan S has opened the door to a new future, but the academic community must walk through it with care, vision, and pragmatism.
Conclusion
Plan S arrived on the scene with the promise of a white knight: championing open access, transparency, and democratized knowledge in a world long dominated by costly paywalls. Its bold, uncompromising stance has stirred the academic publishing ecosystem, accelerating progress toward open science.
Yet the reality is nuanced. Plan S faces significant challenges, including inclusivity, academic freedom, practical implementation hurdles, and global coordination. It has encountered resistance from publishers, researchers, and institutions navigating an uneven landscape.
Rather than a perfect hero, Plan S functions more as a disruptive force, a much-needed wake-up call pushing all stakeholders to rethink scholarly communication. Its true legacy may be less about immediate transformation and more about sparking innovation, debate, and gradual, meaningful change.
In this light, Plan S is a white knight in training, still far from flawless but necessary, promising, and catalytic. The journey to open access will not be won overnight or by mandate alone. It will require collaboration, adaptation, and commitment to sustainability and equity. Plan S has swung open the gate; now the global scholarly community must pass through thoughtfully and boldly.
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