The 2016–17 Pro12 (also known as the Guinness Pro12 for sponsorship reasons) was the sixteenth season of the professional rugby union competition originally known as the Celtic League, and the seventh with a four-country format.

[14] Beaten finalists Leinster also saw changes to their backroom staff, with defence coach Kurt McQuilkin leaving the role for personal reasons in August 2016.

[17] After taking over the captaincy when Kevin McLaughlin was forced to retire, Isa Nacewa was appointed as team captain on a permanent basis ahead of the season opener.

Johan "Rassie" Erasmus joined as Director of Rugby from his role as high performance manager with South Africa, while Jacques Nienaber is the new defence coach.

[21] On 16 October 2016, Anthony Foley died suddenly in the Munster team hotel in Paris while on an away trip to play Racing 92 in the European Champions Cup.

[29] After discussions of a possible move from Murrayfield to Easter Road in 2015 did not come to fruition,[30][31] it was announced in May 2016 that Edinburgh had agreed a partnership with George Watson's College and would play their home fixtures at the school's 6,000 capacity Myreside venue in the second half of the season.

[37] It was announced in October 2016 that this would be Gregor Townsend's last year in charge of Glasgow Warriors as he would depart at the end of the season to take up the role of Scotland head coach.

Cardiff Blues head coach Danny Wilson made seven signings for next season with Kirby Myhill, George Earle and Steven Shingler joining from the Scarlets, Rhys Gill from Saracens, Nick Williams from Ulster, Matthew Morgan from Bristol and Willis Halaholo from the Hurricanes.

The Ospreys added Bradley Davies, Hugh Gustafson and former Scarlets forwards Rhodri Jones and Rob McCusker to their playing staff.

Other new signings included Rhys Patchell, Werner Kruger and Jonathan Evans, while New Zealander Johnny McNicholl arrived later in the season.

After 40 minutes of play, the match was "abandoned due to adverse weather conditions causing considerable risk to both the players and spectators".