The 2011 Rugby World Cup was an international rugby union tournament held in New Zealand from 9 September until 23 October 2011. This article lists the official squads for the 2011 Rugby World Cup in New Zealand. Each of the twenty nations was required to confirm its 30-man squad by 23 August; only players in these squads were eligible to take part in the tournament.
Under competition rules, replacements are made only for medical or compassionate reasons. To implement a replacement the team completes a form and sends it to Rugby World Cup along with a medical certificate where appropriate. Once signed off, the replacement is not allowed to play for 48 hours and the replacement is permanent.
Players marked (c) were named as captain for their national squad. Number of caps and players' ages are indicated as of 9 September 2011 – the tournament's opening day.
The tournament was played during the Super Rugby off season. Players who were released or changed clubs are out-of-contract with their clubs and finished with their 2011 clubs, and in-contract with their national unions and/or future clubs for the 2012 (2011–12 in the Northern Hemisphere) season. Players were listed with their current affiliations as of the opening day of the tournament on 9 September (with some on-going updates during the tournament).
Three squads were made up entirely of players from home-based clubs. Two of these, Australia and New Zealand, had players who signed with overseas clubs for the 2011–12 northern hemisphere season. However, all players on both squads played for clubs within their country, either in Super Rugby or New Zealand's domestic ITM Cup, in the preceding 2011 season. In addition, these players remained under contract with their national unions until the end of the World Cup. The third such squad, France, consists entirely of players under contract with French clubs in both 2010–11 and 2011–12.
Japan's 30-man squad for the 2011 Rugby World Cup was named on 22 August. Justin Ives and Ryukoliniasi Holani were ruled out with injury, they were replaced by Yuji Kitagawa and Toetsu Taufa. Tomoki Yoshida and Yuta Imamura were ruled out with injury, they were replaced by Ippei Asada and Bryce Robins.
The 30-man squad for the RWC was announced on 18 August, with James Horwill replacing Rocky Elsom as the new captain. Wycliff Palu and Drew Mitchell were ruled out after the Russia test, Hodgson and Turner replaced them.
Taylor Paris of Canada was the youngest player named to a squad at 18, while Russia's Viacheslav Grachev, 38, was the oldest. However, Paris did not appear in any of Canada's matches, making Wales' 19-year-old George North the youngest to actually appear in the World Cup.