Penarth RFC will play their next game at Cardiff Arms Park on Saturday, following the fire at the Athletic Club.
The Division One Cup tie against Lampeter Town will mark the Bears' first game since the clubhouse on Lavernock Road suffered significant damage in the early hours of Monday morning.
Three crews were sent to tackle the blaze, which according to South Wales Fire and Rescue Service, was caused by an electrical fault.
Club officials said the WRU will also be providing supporters' buses to and from the Athletic Club, with kick-off moved to the later time of 5.30pm.
On the same day, Cardiff RFC will be playing North Wales club RGC in their latest Super Rygbi Cymru fixture (2.30pm kick off).
A spokesperson for Penarth RFC said: "The support from every rugby club, not just in Wales from all over has been amazing and just shows how important we as rugby clubs and all the people involved are in the community."
Meanwhile, a crowdfunding appeal to help rebuild the clubhouse and replace lost equipment and memorobilia has now raised more than £13,000, having reached its initial target of £10,000 in the 36 hours since the fire.
Earlier, officials at Penarth Athletic Club said the main room of the clubhouse suffered the most significant damage, but it will be made safe and cleaned by the weekend.
The Long Room is undergoing a deep clean after suffering only smoke damage and it's hoped the club will reopen on Sunday morning to allow the junior sections to go ahead with their training.
A spokesperson for the Athletic Club said: "Due to the extent of the damage and the specialist work required, professional contractors are needed. However, we are incredibly grateful for the many offers of help from the community."
They added: "We truly appreciate all the offers of support for the club, our staff, and our members. We will be reaching out as soon as we have a clearer route forward."
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