| Seat | Before | Change | After | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Member | Party | Type | Date | Date | Member | Party | |||
| Vic (Senate) | Stephen Conroy | Labor | Resignation | 30 September 2016 | 25 October 2016 | Kimberley Kitching | Labor | ||
| SA (Senate) | Bob Day | Family First | Resignation, disqualification | 1 November 2016 | 19 April 2017 | Lucy Gichuhi | Family First | ||
| WA (Senate) | Rod Culleton | One Nation | Departure from party | 18 December 2016 | Rod Culleton | Independent | |||
| Independent | Disqualification | 11 January 2017 | 27 March 2017 | Peter Georgiou | One Nation | ||||
| SA (Senate) | Cory Bernardi | Liberal | Formation of new party | 7 February 2017 | Cory Bernardi | Conservatives | |||
| SA (Senate) | Lucy Gichuhi | Family First | Refusal to join party merger | 3 May 2017 | Lucy Gichuhi | Independent | |||
| WA (Senate) | Scott Ludlam | Greens | Resignation, disqualification | 14 July 2017 | 10 November 2017 | Jordon Steele-John | Greens | ||
| Qld (Senate) | Larissa Waters | Greens | 18 July 2017 | 10 November 2017 | Andrew Bartlett | Greens | |||
| WA (Senate) | Chris Back | Liberal | Resignation | 31 July 2017 | 16 August 2017 | Slade Brockman | Liberal | ||
| Qld (Senate) | Malcolm Roberts | One Nation | Disqualification | 27 October 2017 | 10 November 2017 | Fraser Anning | One Nation | ||
| New England | Barnaby Joyce | National | 2 December 2017 | Barnaby Joyce (re-elected) |
National | ||||
| NSW (Senate) | Fiona Nash | National | 22 December 2017 | Jim Molan | Liberal | ||||
| SA (Senate) | Nick Xenophon | Xenophon Team | Resignation | 31 October 2017 | 14 November 2017 | Rex Patrick | Xenophon Team | ||
| Tas (Senate) | Stephen Parry | Liberal | Resignation, disqualification | 2 November 2017 | 9 February 2018 | Richard Colbeck | Liberal | ||
| Bennelong | John Alexander | Liberal | Resignation | 11 November 2017 | 16 December 2017 | John Alexander (re-elected) |
Liberal | ||
| Tas (Senate) | Jacqui Lambie | Lambie Network | Resignation, disqualification | 14 November 2017 | 9 February 2018 | Steve Martin | Independent | ||
| SA (Senate) | Skye Kakoschke-Moore | Xenophon Team | 22 November 2017 | 16 February 2018 | Tim Storer | Independent | |||
| Qld (Senate) | Fraser Anning | One Nation | Departure from party | 15 January 2018 | Fraser Anning | Independent | |||
| NSW (Senate) | Sam Dastyari | Labor | Resignation | 25 January 2018 | 14 February 2018 | Kristina Keneally | Labor | ||
| Batman | David Feeney | Labor | Resignation | 1 February 2018 | 17 March 2018 | Ged Kearney | Labor | ||
| SA (Senate) | Lucy Gichuhi | Independent | Party membership | 2 February 2018 | Lucy Gichuhi | Liberal | |||
| Qld (Senate) | George Brandis | LNP | Resignation | 8 February 2018 | 21 March 2018 | Amanda Stoker | LNP | ||
| ACT (Senate) | Katy Gallagher | Labor | Disqualification | 9 May 2018 | 23 May 2018 | David Smith | Labor | ||
| Perth | Tim Hammond | Labor | Resignation | 10 May 2018 | 28 July 2018 | Patrick Gorman | Labor | ||
| Braddon | Justine Keay | Labor | Resignation | Justine Keay (re-elected) |
Labor | ||||
| Fremantle | Josh Wilson | Labor | Josh Wilson (re-elected) |
Labor | |||||
| Longman | Susan Lamb | Labor | Susan Lamb (re-elected) |
Labor | |||||
| Mayo | Rebekha Sharkie | Centre Alliance | 11 May 2018 | Rebekha Sharkie (re-elected) |
Centre Alliance | ||||
| Tas (Senate) | Steve Martin | Independent | Party membership | 28 May 2018 | Steve Martin | National | |||
| Qld (Senate) | Fraser Anning | Independent | Party membership | 4 June 2018 | Fraser Anning | Katter's Australian | |||
| NSW (Senate) | Brian Burston | One Nation | Departure from party | 14 June 2018 | Brian Burston | Independent | |||
| Independent | Party membership | 18 June 2018 | United Australia | ||||||
| NSW (Senate) | Lee Rhiannon | Greens | Resignation | 15 August 2018 | Mehreen Faruqi | Greens | |||
| Qld (Senate) | Andrew Bartlett | Greens | Resignation | 27 August 2018 | 6 September 2018 | Larissa Waters | Greens | ||
| Wentworth | Malcolm Turnbull | Liberal | Resignation | 31 August 2018 | 20 October 2018 | Kerryn Phelps | Independent | ||
| Qld (Senate) | Fraser Anning | Katter's Australian | Departure from party | 25 October 2018 | Fraser Anning | Independent | |||
| Chisholm | Julia Banks | Liberal | Departure from party | 27 November 2018 | Julia Banks | Independent | |||
| Tas (Senate) | David Bushby | Liberal | Resignation | 21 January 2019 | 6 March 2019 | Wendy Askew | Liberal | ||
| Vic (Senate) | Jacinta Collins | Labor | Resignation | 15 February 2019 | Raff Ciccone | Labor | |||
| NSW (Senate) | David Leyonhjelm | Liberal Democrats | Resignation | 1 March 2019 | 20 March 2019 | Duncan Spender | Liberal Democrats | ||
| Qld (Senate) | Fraser Anning | Independent | Formation of new party | 4 April 2019 | Fraser Anning | Conservative National Party | |||
| ACT (Senate) | David Smith | Labor | Resignation | 11 April 2019 | vacant | ||||
| SA (Senate) | Cory Bernardi | Conservatives | Party deregistration | 24 June 2019[a] | Cory Bernardi | Independent | |||
- ^ The party deregistration was after the 2019 election but before the start of the 46th Parliament