Most councils in Wales are breaking the law by failing to offer Welsh language swimming lessons at their leisure centres, according to campaigners.
Under new regulations the councils have a duty to offer educational courses open to the public in Welsh.
But according to a survey conducted by Cymdeithas yr Iaith Gymraeg more than half of councils are failing to do so.
In an official complaint to Welsh Language Commissioner Meri Huws, the group's spokesperson said: 'It’s clear that a number of councils are breaking their legal duties to expand the use of Welsh in sports and leisure activities.
'We ask you to conduct an inquiry into this situation in general, reminding every local council of the need to offer courses in Welsh and make a pro-active offer as well.'