The National Urdd Eisteddfod in Denbigh has been postponed until 2021 and all regional Urdd events have been cancelled due to coronavirus fears.
11,000 young people participate in Urdd community sports clubs every week and more than 68,000 compete in the Urdd Eisteddfod.
The Urdd has closed all three of its residential centres (Llangrannog, Cardiff and Glan-llyn) from Friday 20 March until further notice and has cancelled all local and regional Eisteddfodau.
It has also decided to cancel all national sports competitions and community activities until further notice.
The Urdd provides opportunities for children and young people to take part in a range of experiences through the medium of Welsh.
The Urdd say they now face a significant financial challenge and expect to lose nearly £4 million from these measures. It is the largest Welsh language employer in Wales' third sector and is worth more than £31 million to the economy.