Exemptions, the ECHR said, are ‘justified only in very exceptional circumstances’.
‘Accordingly, the children’s interest in a full education, thus facilitating their successful social integration according to local customs and mores, prevailed over the parents’ wish to have their children exempted from mixed swimming lessons,’ the court said.
The court said that ‘very flexible arrangements’ have been offered, including allowing the girls to use a girls-only changing room and letting them wear burkinis during lessons instead of traditional swimwear.
Education officials said that exemptions from swimming lessons were only available to girls who had reached puberty.
The Swiss nationals’ daughters had not reached puberty when their parents kept them from swimming lessons.
In 2010, the parents had to pay a fine of almost €1,300 (£1,100) ‘for acting in breach of their parental duty’.
At the time, the parents said the fine was a violation of their human rights, particularly article nine of the European Convention on Human Right.
Article nine covers the right of freedom of thought, conscience and religion.
In 2012, Switzerland’s highest court in Lausanne ruled that the obligation to attend mixed-gender swimming lessons was not a violation on religious freedom.