Summer entertainments in Llandrindod Wells were provided in temporary marquees at the Rock Park before 1912, when the Grand Pavilion opened.
The new building had ample space for concerts, dances and theatre shows. It originally boasted an external balcony at first-floor level which circled the entire building. Lord Baden-Powell stood on the balcony in 1933 to address a Boy Scout jamboree.
During the First World War, whist drives (whist is a card game for pairs of players) were held at the Grand Pavilion to raise funds for the Blue Cross, which cared for animals in military service. The army still depended on horses for heavy transport. Dogs served at the front in many capacities, including as rat catchers, sentries, mascots and sniffers-out of enemy soldiers or explosives. Public donations enabled the Blue Cross to treat more than 50,000 horses and 18,000 dogs during the war,
and to send horse medicines to army units around the world.
In December 1916 local farmers donated livestock, produce and furniture for auction at the Pavilion, raising more than £100 for both the Red Cross and Blue Cross.
The Pavilion was used for lectures by the Royal Army Medical Corps, which billeted c.4,000 men in Llandrindod Wells for training in 1915-16. More than 2,000 men, mostly from the RAMC, packed into the pavilion in March 1915 for an RAMC boxing tournament. Concerts given here by RAMC men were well received, some of the men being actors and musicians by profession! The RAMC’s farewell concert, held here in May 1916, also drew a large audience.
The Pavilion functioned as a cinema from the 1920s to the 1950s, after which it was primarily a dance hall. Powys County Council ran the Pavilion from the 1970s until 2015 as a venue for conferences, discos, comedy and other events. On June 10th 1977, The Stranglers, a UK Punk Rock band played to a sellout crowd as part of their UK Tour. Other notable names to have performed here during it's heyday were Ken Dodd, Jasper Carrott, XTC.