The Urdd Eisteddfod has set up a hotline following concerns about traffic delays.
Long queues delayed competitors’ and visitors’ entry to the event at Bridgend College’s Pencoed campus on Tuesday.
Organisers said anyone heading to the festival who is running late for a competition should call 0345 257 1639 or email firstname.lastname@example.org.
The preliminary competitions could then be delayed until they arrive.
Director of the Welsh language youth festival Aled Sion said Tuesday had been expected to be the busiest day.
The event runs until 3 June and is expected to bring in 100,000 visitors over the course of the week.