1 January – Welsh recipients of New Year Honours include Raymond Rees (MBE), for his role in preserving the tradition of coracle fishing; Tom Davies (OBE), commissioner of the Independent Police Complaints Commission in Wales; Peter Walker, former Glamorgan cricketer (MBE); educator Dr Dennis Gunning (CBE); and Gareth Vaughan, president of the Farmers’ Union of Wales (MBE).[5] Professor Eldryd Parry is made a KCMG for his services to medicine.
3 March – Welsh devolution referendum: Of a 35.2% voting turnout, 63.49% vote 'yes', and 36.51% vote 'no' in response to the question "Do you want the Assembly now to be able to make laws on all matters in the 20 subject areas it has powers for?".
15 March – Local Government Minister Carl Sargeant confirms to the National Assembly that Anglesey Council will be taken over by independent commissioners as a result of infighting between councillors. Sargeant says that the councillors have "betrayed those who elected them" and indulged in "politics of the playground".[10]
Elizabeth II visits Anglesey to witness the daily activities of her grandson, Prince William of Wales. She arrives at RAF Valley in gale-force winds. The prince comments: “I really do love it here”.[13]
20 April – Four people from Pontypridd are killed when their car plunges down an embankment and into the Clywedog reservoir.[14]
17 May – Two newly elected Lib Dem AMs, Aled Roberts and John Dixon, are discovered to have been ineligible for election to the Assembly, because of their membership of other bodies.[17]
25 June – Archdruid T. James Jones makes a controversial speech in which he claims that "Britishness" threatens Welsh identity, and suggests that Welsh Olympic medal-winners should be accompanied by the raising of the Welsh flag and the Welsh national anthem, rather than the British flag and anthem. Welsh Conservative MP David Davies says he is "talking rubbish" and that most Welsh people are proud to be both British and Welsh.[19]
29 June – A court ruling restricting the powers of police bail has thrown thousands of cases in England and Wales into disarray.[20]
17 August – Paralympic cyclist Simon Richardson MBE is seriously injured in a road accident near Cowbridge, ten years after a similar accident that left him disabled.[22]
30 August – Racecourse owner Dai Walters warns that Ffos Las, the UK's newest racecourse, could be forced to close if plans to reduce the number of race meetings are carried through.[23]
2 September – Welsh Food Festival is held at Glansevern Hall, Welshpool.[24]
28 November – The judge in the trial of eight former South Wales Police officers accused of perverting the course of justice in the 1988 Lynette White murder case requests a review of evidence. It is discovered that some files are missing, and the case against the defendants collapses as a result.[31]
30 November – About 170,000 workers in Wales begin a strike as part of UK-wide industrial action over pension changes.[32]
17 December – A walker dies in an avalanche on Y Garn, in Snowdonia, despite rescue attempts by helicopter and emergency services.[33] A woman escapes with her life in the same incident.
15 October – Wales are defeated 9–8 by France in the semi-final of the 2011 Rugby World Cup, in a controversial match during which captain Sam Warburton is sent off for a dangerous tackle.
20 October – Wales are defeated 21–18 by Australia in the third-place final of the 2011 Rugby World Cup.
3 December – Shane Williams plays his last match for Wales, against Australia, scoring his 58th try in the final minutes of the match.