[1] The twelve teams in the RFU Championship also competed in the British and Irish Cup, along with clubs from Ireland and Wales.

[2] On 7 April 2018 Bristol were crowned champions with 2 games to go following title rivals Ealing Trailfinders defeat that day to Doncaster Knights.

[7][8] As a result, Rotherham Titans, who finished bottom of the league, were not relegated; a decision which former Championship club Plymouth Albion contested.

[9][10] Promoted in place of London Welsh were the winners of 2016–17 National League 1, Hartpury College, who have moved from Gloucester 3 North, at the bottom of the English rugby pyramid, to the second tier within thirteen years of their founding.

[11][12] London Irish was promoted as champions and play-off winners of the 2016–17 RFU Championship and were replaced by Bristol following their last place in the 2016–17 English Premiership.