|Birth name||Viliami Vunipola|
|Date of birth||3 November 1992|
|Place of birth||Sydney, Australia|
|Height||1.88 m (6 ft 2 in)|
|Weight||130 kg (20 st 7 lb; 290 lb)|
|School||The Castle School|
|Notable relative(s)||Feʻao Vunipola (father)|
Mako Vunipola (brother)
|Rugby union career|
Vunipola was born in Sydney, New South Wales, Australia to Tongan parents, but moved to Wales with his family as a child. He was educated at Porth Infants School and Griffithstown Junior School, and subsequently The Castle School in Thornbury, England, and played junior rugby for Thornbury RFC before winning a scholarship to attend Harrow School.
While at Harrow School, Billy joined the Wasps Academy. He made his senior team debut in 2011–12 season and played 30 matches over two seasons before leaving at the end of the 2012–2013 season.
After representing England at U18 and U20 level, Billy was called up to the England Saxons Squad in January 2013. He trained with the England Squad during the 2013 Six Nations Championship and made his senior England debut during the England tour of Argentina in the test against Argentina in Salta in June 2013, coming off the bench to score a try in England's 32–3 win. Earlier in the tour he played in an un-capped match against a Consur XV, in this match he completed a hat-trick in six minutes.
British and Irish Lions
In April 2017, Vunipola was selected as the one of the 41 British and Irish Lions to tour New Zealand in the summer alongside with his brother Mako Vunipola. However due to an ongoing shoulder injury, he later withdrew from the squad on 21 May 2017 and was replaced by England back-row teammate James Haskell.
Vunipola's father is former Tongan captain Fe'ao Vunipola and Methodist Minister, Rev. Iesinga Vunipola (who is also Chaplain to the UK Tongan Community). He is the nephew of two other former international players, Manu and 'Elisi Vunipola who both represented Tonga in the 1990s. His brother, Mako Vunipola is his teammate and plays at prop for Saracens and England.
- "Billy Vunipola". Retrieved 14 September 2017.
- "England v Italy: Vunipola brothers Mako and Billy want Mum to see their Sunday best". Daily Telegraph. 7 March 2013.
- "Billy Vunipola hopes to confirm brotherly love for Saracens". thetimes.co.uk. Retrieved 19 January 2018.
- "Argentina 3–32 England". espn.co.uk. Retrieved 11 June 2013.
- Robert Kitson. "Chris Robshaw set to be confirmed as England captain for Australia clash | Sport". The Guardian. Retrieved 2014-02-02.
- "Billy Vunipola withdraws from Lions squad". British and Irish Lions. Retrieved 21 May 2017.