Entry was free into the home of Welsh rugby and the public not only got up close and personal with the squad but got to see how they prepare ahead of a test match.
Wales take on the might of all three Tri-Nations side's next month as well as Pacific Islanders, Fiji.
WRU chief executive Roger Lewis was delighted with the turn out at the unique event and predicted there would be similar sessions in the future.
"Today is the first time we have opened a full training session to the Welsh public and it has been fantastic", said Lewis.
"We have the best rugby supporters in the world and we wanted to give them something for free,
"It was a full-on, proper training session out there today and I think everyone enjoyed themselves and we are certainly thinking about doing it again."
Tickets are currently still available for all four of Wales' Invesco Perpetual Series matches against Australia (Sat 6 Nov 2.30pm), South Africa (Sat 13 Nov 2.30pm), Fiji (Friday 19 Nov 7.30pm) and New Zealand (Sat 27 Nov 5.15pm).
Ticket-only packages are available in Thomas Cook and Going Places stores around Wales and the UK.
Tickets are also available online by clicking here by phoning 08442 777888 or by calling into the WRU's cafe/store, The Cardiff Arms, 8 Westgate Street, Cardiff.