COST Open Call 2026: two network composition rules

The COST Open Call 2026 opened on 31 July and runs until 28 October 2026 at 12:00 noon CET. Up to 80 new COST Actions will receive funding, meaning four-year interdisciplinary research networks in any field of science and technology.

This year COST added a mandatory condition that did not exist before: at least 40 per cent of proposers in a network must be Young Researchers and Innovators. Together with the long-standing requirement that half the network comes from Inclusiveness Target Countries, the composition of a network now decides the fate of a proposal as much as its scientific quality does.

So this guide covers the arithmetic of network composition, the three procedural changes of 2026, and why a Ukrainian team ends up in a strong position under this configuration.

What changed in 2026

COST warns directly that the procedure has been updated and advises even experienced proposers to reread the documents. The changes cover three things.

The new condition: 40 per cent young researchers

First, at least 40 per cent of network proposers must belong to the Young Researchers and Innovators category. COST defines it by age: 40 years old or younger.

This is an additional requirement, and the old one has not gone anywhere. So a network now satisfies two structural conditions at once, one geographic and one demographic. A team that assembled its consortium under last year rules may find the composition formally fails.

The Technical Annex is no longer a separate document

Also the Technical Annex now sits inside the submission process, and you complete it directly in the e-COST platform. No separate file needs uploading.

No budget plan at the submission stage

Another change that visibly cuts preparation effort. The submission needs no budget plan. In addition, the system blocks submission if page and text limits are exceeded, so the system now rules out a formal rejection on that ground.

The two composition rules that decide everything

COST states the requirements for a network of proposers plainly, and these are where proposals most often stop.

At least 7 member countries

In total a network of proposers must comprise at least 7 COST Full or Cooperating Members. This counts countries: seven different member countries in the composition, whatever the number of organisations.

At least 50 per cent from Inclusiveness Target Countries

In practice half the composition must come from Inclusiveness Target Countries, or ITCs. These are the less research-intensive COST member countries whose participation the programme actively promotes. Ukraine belongs to that list, and it is also a full COST member.

The arithmetic in practice

So take the minimum configuration. With 7 countries the 50 per cent rule means at least 4 from the ITC list, because half of seven is three and a half while the requirement reads as no less than. At the same time 40 per cent of proposers must be young researchers.

The consequence worth seeing at once. A network of seven countries with only three ITCs fails. A network with enough ITCs but fewer than 40 per cent of proposers under 40 also fails. Assessors check both conditions, and neither compensates for the other.

One more restriction people forget: within a single Open Call an individual may take part in one proposal only, either as Main or as Secondary Proposer. So writing one strong colleague into three different consortia will not work.

Why a Ukrainian team holds a strong position here

So Ukraine gains a double advantage in this configuration, which is rare among European programmes.

First, the consortium needs you. Ukrainian participation here is neither a concession nor a quota, since it forms a condition of eligibility. A network one ITC country short of half its composition looks for such a country actively. That creates a fundamentally different negotiating position from calls where a Widening country joins as a welcome yet optional partner.

Second, the new age condition also works in your favour. The requirement that 40 per cent of proposers be aged 40 or under pushes coordinators to look for younger researchers, and Ukrainian research groups fill that niche.

Third, there are no thematic restrictions. COST sets no priority areas. A proposal can address any field of science and technology, including new interdisciplinary areas. That removes the main obstacle of other programmes, where the theme of a round misses the profile of a team.

In addition the range of eligible entities is broad. Under the official call announcement these include national, regional and local public authorities, universities, research centres, small and medium-sized enterprises, large companies, non-governmental organisations and any other legal entity recognised under a national or international framework.

What COST funds and how much it gives

Here sits the misunderstanding that leads teams to prepare the wrong proposal. COST funds networking activity. The research itself falls outside the programme. Specifically, the money goes to meetings, Short-Term Scientific Missions, Training Schools, communication activity and virtual collaboration tools.

In total funding runs at roughly EUR 150,000 for the first year and an average of EUR 180,000 for each of the following three. Across four years that comes to approximately EUR 690,000 per network.

The practical conclusion. A proposal built as a description of a research project, with work packages and research results, misses the logic of the programme. Assessors look at the value of the network itself: who it brings together, what gaps it closes, what participants gain from the collaboration.

COST works well as a preparatory step, though. A network delivers a ready consortium, joint publications and working contacts, which a team can then carry into the large Horizon Europe calls.

The procedure and the calendar

Overall submission is single stage and fully online through the e-COST platform. There are no separate concept and full application phases here.

Then independent external experts carry out the evaluation. The COST Committee of Senior Officials takes the funding decision within 7 months of the collection date, meaning from 28 October. Finally, results are expected in May 2027, and approved networks start roughly 4 months after approval.

What this means for planning. Roughly 11 months pass between submission and the start of work. So assemble the network around a scientific problem that will still matter in a year, instead of around a current moment.

The updated documents, including the proposers guidelines and the call announcement, sit in the Documents and Guidelines section. COST specifically advises rereading them even if you have applied before.