The 2016–17 Principality Premiership was the first season of the new format of the Principality Premiership, the top tier of club rugby in Wales run by the Welsh Rugby Union. It was contested by sixteen Welsh clubs following an expansion from twelve teams. The next two seasons will be "ring-fenced" and will have no relegation until the 2018–19 season. The competition was won by Merthyr in their first season in the Premiership. The second-tier competition was won by Newport who won their first silverware since the 2003–04 Premiership season.