Cardiff Rugby

Principality Stadium, known until its renaming as the Millennium Stadium, holds 74,500. Cardiff Rugby are its home side, and the shirt they wear there is a light blue base with black hoops. Between 2003 and 2021 the blue was a different shade, called Cardiff blue. It went back to Cambridge blue when the name changed from Cardiff Blues to Cardiff Rugby in 2021, which is also when the "Blue & Blacks" nickname came back into ordinary use.

The professional side dates from 2003, when the Welsh regional structure was set up. The lineage runs further back, to Cardiff Football Club in 1876. It was formed from a merger of Glamorgan and Wanderers, and its first match, against Newport on 2 December 1876, gave Welsh rugby a fixture that still exists. That older club is the reason the World Rugby Hall of Fame, which inducted it in 2011, lists Gwyn Nicholls, Cliff Morgan, Gareth Edwards, Barry John and Gerald Davies in its history.

The regional era has produced two European Rugby Challenge Cup wins: over London Wasps in 2010 and over Gloucester in 2018. Gloucester were also beaten 50–12 at Twickenham in the 2009 Anglo-Welsh Cup final.

In 2005 Jonah Lomu played for the club while recovering from a kidney transplant. Matches against the Scarlets are the Welsh Derby, and those against the Dragons are the East Wales Derby. Both sit within the "Judgement Day" fixtures.

Ben Blair is the club's top scorer with 1,075 points. Tom James has scored the most tries, 60. Lloyd Williams has made 256 appearances.