Can I wear headphones in a cross country race?

No. Under UKA Rule TR56 S3(3), headphones or similar devices are not permitted in cross country races. Runners who break this rule are liable to disqualification.

The only exception is a device used following a medical diagnosis, supported by a recommendation from a medically qualified professional.

This is stricter than road racing, where bone-conduction headphones that leave the ears clear are acceptable unless the organiser rules them out.