Patients may be waiting months for NHS operations unaware they could get the health service to pay for quicker treatment in Europe.
Under European law, UK patients who are clinically eligible for NHS treatment can seek it in other EU countries.
They can also reclaim costs of up to what the NHS would have spent.
But fewer than 30 patients in Wales have made such applications during the past three years, BBC Wales has found.
There are concerns that patients and even some medical professionals are not aware of the rules.
Certain procedures require patients to get prior approval from their health board.
The European directive for cross-border treatment came into force in Wales in October 2013 and allows patients to be reimbursed for care in a state-run or private hospital.
It also places a duty on the Welsh government and NHS to provide easily accessible information to patients about their rights.
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