The Court of Arbitration for Sport sits in Lausanne, and that single fact decides how its awards can be challenged. An appeal does not go to a sports body or to a court in the athlete's own country. It goes to the Swiss Federal Supreme Court, under article 190 of the Swiss Federal Act on Private International Law — and the grounds in article 190(2) are exhaustive. Anything not on the list is not an argument, however strong it is.
The five grounds
- Irregular constitution of the tribunal — the sole arbitrator or the panel was appointed improperly.
- Want of jurisdiction — the tribunal wrongly accepted or wrongly declined jurisdiction.
- Ultra or infra petita — the award went beyond the claims submitted, or failed to decide one of them.
- Equal treatment and the right to be heard — a party was not treated equally, or was not given the opportunity to present its case.
- Public policy — the award is incompatible with public policy, substantive or procedural.
What is not on the list
The merits. The court does not review whether the panel weighed the evidence correctly, whether the sanction was proportionate in the ordinary sense, or whether the rule applied was a good rule. An applicant arguing that the panel got the facts wrong is arguing something article 190 does not recognise.
The numbers behind the odds
In 2025 the Federal Supreme Court decided 31 applications to set aside international arbitral awards, and one was overturned — on the right-to-be-heard ground, article 190(2)(b) in the court's numbering of the grounds. That ratio is the realistic answer to «can this be appealed»: formally yes, on five grounds, and in practice almost never on the merits, because the merits are not a ground.
Why the sports system is built this way
A single seat of arbitration with a single supervisory court gives the same reading of the same rules to athletes from every country. The price is that national courts are largely out of the picture, and the review that remains is procedural. That is also why the compliance machinery described in Non-compliance is not a sanction routes its own disputes to CAS, and why the distinction in Provisional suspension is not ineligibility matters so much in practice: the interim decision is often the one the athlete actually lives with.
Where this is written: article 190 and article 190a of the Swiss Federal Act on Private International Law, fedlex.admin.ch; procedural rules of the Court of Arbitration for Sport at tas-cas.org.