What you actually get
Public AI compute programmes award an allocation of GPU hours on a specific supercomputer for a fixed period. You don't receive money, and unused hours don't carry over. For example, Isambard-AI and Zenith (AIRR) Gateway route awards projects the following: Up to 10,000 GPU hours on the Isambard-AI and Zenith supercomputers, used within three months; no funding.
That makes these routes good for training runs, benchmarking and experiments with a clear plan, and less useful if you need a steady, long-running production service. For that, commercial credit programmes are usually a better fit: see the compute credits guide.
UK: Isambard-AI and Zenith (AI Research Resource)
UKRI runs two always-open routes onto the Isambard-AI and Zenith supercomputers:
- Gateway route. Isambard-AI and Zenith (AIRR) Gateway route: Up to 10,000 GPU hours on the Isambard-AI and Zenith supercomputers, used within three months; no funding. It is open to UK-based researchers from academia, industry and other organisations, and is aimed at first-time users, testing and benchmarking before applying for larger allocations.
- Rapid Access route for SMEs. Isambard-AI and Zenith (AIRR) Rapid Access route for UK SMEs: 20,000 GPU hours on the Isambard-AI and Zenith AIRR supercomputers, used within three months; no funding. It is for researchers at UK-registered micro, small and medium businesses developing AI products before market launch.
Both have no closing date, and both need the project lead to have a contract with their organisation that lasts longer than the project.
EU: EuroHPC AI Factories
The EuroHPC Joint Undertaking offers access to its AI Factories in several modes:
- Playground access (EuroHPC AI Factories Playground Access) is for SMEs, startups and entry-level users with small needs. Applications are handled first come, first served, with no competitive selection, and EuroHPC says access can be granted within two working days. Allocations last one, two or three months on a single system.
- Large Scale access (EuroHPC Large Scale Access to AI Factories) is for big GPU allocations, with regular cut-off dates through the year.
Demand is high. On 2 November 2026 EuroHPC's access page said MareNostrum and LUMI-G were unavailable for new allocations in its Fast Lane call because of exceptionally high demand, so be ready to pick another system.
US: the NAIRR Pilot
In the US, NAIRR Pilot: Advancing AI Research Resources offers 12-month allocations of computing, model, platform and educational resources. It is for US-based researchers and educators at US institutions, including graduate students with an advisor letter, and some non-profits and startups with federal grants. An institutional email is required.
Side by side
| Route | Who it's for | What you get | Speed |
|---|---|---|---|
| Isambard-AI Gateway (UK) | UK-based researchers in academia, industry and other organisations | Up to 10,000 GPU hours for 3 months | Open all year |
| Isambard-AI Rapid Access (UK) | UK-registered SMEs building AI products | 20,000 GPU hours for 3 months | Open all year |
| EuroHPC Playground (EU) | SMEs, startups and entry-level users | Small allocations for 1 to 3 months | Within 2 working days |
| EuroHPC Large Scale (EU) | Projects needing large GPU allocations | Large allocations per call | Cut-offs through the year |
| NAIRR Pilot (US) | US-based researchers and educators | 12-month allocations of compute and other resources | Rolling |
Figures as stated on each programme's page when we checked it. Follow the links for the current terms.
How to make the most of an allocation
- Size the job before you apply. Work out roughly how many GPU hours your runs need, and whether they fit in the allocation window.
- Start small. Use an entry route such as the Gateway or Playground to test your code on the system, then apply for more.
- Have your software ready. Time spent installing and debugging counts against a short allocation.
- Combine routes. Researchers can pair public compute with research credit programmes such as Google TPU Research Cloud (TRC) or Nebius Research Grants; startups often add cloud credits.