What Is Plan S? OA Mandate Explained

Plan S is a funder-driven open access mandate developed by cOAlition S, a group of national research funders, charitable foundations, and the European Commission, requiring that research outputs from the grants they fund be made immediately and freely available with no embargo period, typically under a CC BY license. Rather than a single law or a publisher policy, Plan S is a coordinated commitment by its member funders to make immediate open access a condition of receiving their money.

Who created Plan S, and why

Plan S was announced on 4 September 2018, developed under the leadership of the European Commission’s then Open Access Envoy Robert-Jan Smits together with Science Europe and a group of national funding organisation leaders. The coalition that formed to implement it, cOAlition S, comprises European national research funders, the European Research Council, and the European Commission, and was later joined by funders and foundations outside Europe, including the Wellcome Trust and the Bill & Melinda Gates Foundation. The “S” in Plan S is commonly said to stand for “Science, Speed, Solution, Shock” — a deliberate signal that the coalition intended immediate, decisive change to the subscription-journal publishing model rather than a slow transition.

The original 2018 announcement was revised in 2019 following a public consultation with the research and publishing community, which softened some implementation details (for example, extending timelines and clarifying how hybrid and transformative journals would be treated) while keeping the core immediate-OA principle intact.

The core Plan S principle: no embargoes, CC BY by default

Plan S’s central requirement is that publications reporting on cOAlition S-funded research must be openly available at the time of publication, with no embargo period. This is a stricter position than many earlier funder policies (including the original NIH Public Access Policy), which historically permitted a delay — commonly 6 or 12 months — before a manuscript had to be made public. Plan S explicitly rejects that model for its member funders’ grants.

The default licensing requirement is Creative Commons Attribution (CC BY), which allows anyone to reuse, redistribute, and build on the work (including commercially) as long as the original authors are credited. CC BY-SA (ShareAlike) or CC0 (public domain dedication) are accepted alternatives; a more restrictive license such as CC BY-ND (No Derivatives) is permitted only as a funder-approved exception, not as a default option. For a full side-by-side comparison of what CC BY actually permits versus a non-commercial variant, see CASRAI’s CC BY vs. CC BY-NC comparison.

The three routes to Plan S compliance

cOAlition S set out several ways a funded researcher can satisfy Plan S, rather than mandating a single publishing venue type:

Publish in a fully open access journal or platform. The output is openly available from the moment of publication with an accepted license, with no separate deposit step required.
Publish in a subscription (or hybrid) journal and deposit a compliant copy immediately in an open repository. The author deposits the Author Accepted Manuscript (AAM) — or the publisher’s Version of Record, if permitted — in an institutional or subject repository at the time of publication, under a CC BY license and with no embargo. This route is what makes the Rights Retention Strategy necessary in practice: because most subscription-journal copyright agreements would otherwise conflict with an immediate, CC BY-licensed deposit, cOAlition S developed the Rights Retention Strategy so funded authors can assert the necessary rights before they ever sign a publisher agreement. CASRAI covers that mechanism, and the conflict it can create with publisher policies, in a dedicated guide: Rights Retention Strategy: The Funder-vs-Publisher Conflict Authors Face.
Publish through a transformative arrangement. cOAlition S has, on a transitional basis, recognised certain transformative journals, transformative agreements (institution- or consortium-level deals that convert subscription spend into open-access publishing spend), and transitional agreements, provided they meet cOAlition S’s own transparency and progress criteria. cOAlition S has been explicit that this route is intended to be temporary, not a permanent parallel track to full open access — funders and publishers should treat any specific transformative arrangement’s current status and end date as something to confirm directly with cOAlition S or the publisher rather than assume, since these arrangements are renegotiated on their own schedules.

Which funders follow Plan S

Plan S applies directly to grants from cOAlition S member organisations. Members and funders that have aligned their own open access policies with Plan S principles include UK Research and Innovation (UKRI), France’s Agence Nationale de la Recherche (ANR), the Netherlands’ NWO, and other national research councils across Europe, alongside major charitable research funders such as Wellcome and the Bill & Melinda Gates Foundation. The Howard Hughes Medical Institute has also aligned its open access requirements with Plan S principles. Plan S is not a single global rule — a researcher’s actual obligation always depends on which specific funder(s) supported the work and what that funder’s own current policy requires, since individual member policies can differ in scope and timing even where they share Plan S’s core immediate-CC BY principle.

It is worth distinguishing Plan S from funder mandates outside the cOAlition S framework. The US National Institutes of Health, for example, operates its own long-standing public access requirement, which historically allowed a 12-month embargo and has its own compliance mechanism (PMC deposit) rather than the CC BY/immediate-deposit model Plan S requires. See CASRAI’s guide to the NIH Public Access Policy for how that mandate’s rules, deadlines, and compliance process differ from Plan S’s.

What Plan S means for researchers in practice

For an author funded even partly by a cOAlition S member (or an aligned funder), Plan S has practical consequences well before a paper is submitted:

Journal choice matters. Before submitting, funded authors typically need to check whether their target journal is fully open access, offers a compliant transformative route, or will require use of the Rights Retention Strategy to deposit a CC BY-licensed manuscript alongside subscription publication.
Article Processing Charges (APCs) are addressed, not ignored. Plan S funders generally commit to covering reasonable publication costs for compliant venues, but expect transparent, capped, or negotiated pricing rather than open-ended APCs — authors should check their specific funder’s APC policy rather than assume any amount is automatically covered.
Copyright retention becomes the author’s (or funder’s) responsibility to assert. Because standard publisher copyright transfer agreements are often incompatible with immediate CC BY deposit, funded authors may need to notify the publisher of funder-mandated rights retention at or before submission, rather than negotiating it after acceptance.
Compliance is typically checked at reporting/renewal, not just at submission. Funders that have adopted Plan S generally verify open access compliance for outputs cited in grant reports, so non-compliant publications can affect future funding decisions, not just the individual paper.

See CASRAI’s related guides on hybrid open access journals and institutional repositories for more on two of the mechanisms researchers commonly use to satisfy a Plan S-aligned mandate.

Criticism and debate

Plan S has been debated within the scholarly communication community since its announcement. Common points raised in that debate include: concern that APC-funded gold open access can shift cost burdens onto authors and their institutions rather than eliminating them; equity concerns for researchers at institutions or in regions without funds to cover APCs, even where waivers exist; and debate over whether time-limited transformative agreements meaningfully shift the underlying subscription-based publishing market or simply relabel existing spending. cOAlition S has responded to some of this by increasing its own attention to Diamond Open Access (publishing models with no author-facing or reader-facing fees) as part of its stated strategic priorities. Readers evaluating Plan S’s effects should treat cOAlition S’s own published monitoring and strategy documents, rather than secondary commentary, as the primary source for how the coalition characterises its own progress.

Current status

Plan S’s core immediate-OA, CC BY-by-default requirement has remained in place since the 2019 revision, and cOAlition S has continued to publish updated guidance and strategy documents rather than retiring or fundamentally rewriting the original principles. Because specific elements — which transformative arrangements remain recognised, current APC-related guidance, and coalition membership — are actively maintained by cOAlition S rather than fixed at the 2018/2019 baseline, readers who need a current, authoritative position on a specific compliance question should check coalition-s.org directly rather than rely on a secondary summary, including this one, as the final word.

Frequently asked questions

Is Plan S a law?

No. Plan S is a funder policy commitment, not legislation. It binds researchers only through the terms of the specific grant(s) that fund their work — it has no force over research that isn’t funded, in whole or in part, by a cOAlition S member or an aligned funder.

Does Plan S apply to US federal funders like NIH or NSF?

No, cOAlition S itself is a coalition of largely European and some international funders and foundations; NIH and NSF are not cOAlition S members and run their own separate public access policies with their own rules and timelines. See CASRAI’s NIH Public Access Policy guide for how that specific US mandate compares.

What’s the difference between Plan S and the Rights Retention Strategy?

Plan S is the overall funder mandate — the policy commitment to immediate, CC BY open access. The Rights Retention Strategy is a specific legal mechanism cOAlition S developed so authors can satisfy Plan S’s Route 2 (subscription-journal publication plus immediate compliant deposit) even when a publisher’s own copyright agreement would otherwise conflict with that requirement. See the Rights Retention Strategy dictionary entry and CASRAI’s dedicated guide on the resulting funder-vs-publisher conflict for detail on how the mechanism itself works.

Do I have to pay an APC to comply with Plan S?

Not necessarily. Plan S compliance can be met through fully open access venues (which may or may not charge an APC), a compliant repository deposit under the Rights Retention Strategy (which typically avoids an APC entirely), or a recognised transformative arrangement. Whether an APC applies, and whether it’s covered, depends on the specific journal and funder policy.

What license does Plan S require?

CC BY is the default requirement, with CC BY-SA or CC0 accepted as alternatives. A more restrictive license, such as CC BY-ND, is only permitted where a funder has granted a specific exception — it is not an option researchers can choose by default.

What Is Plan S? The Open Access Funder Mandate Explained