County ins and outs:
Derbyshire have signed Australian internationals Sean Abbott and Ben McDermott, after losing England U19 international Hamidullah Qadri to Kent.
Ins: Michael Cohen (Western Province), Sean Abbott (Overseas), Ben McDermott (Overseas - Vitality Blast and One-Day Cup)
Outs: Alfie Gleadall (Released), Hamidullah Qadri (Kent), Daryn Smit (Retired), James Taylor (Surrey)
All-rounder Paul Coughlin has returned to Durham after a five-year absence to replace Ryan Pringle, who was part of the side which finished runners-up in the 2016 Vitality Blast.
Ins: Cameron Bancroft (Overseas) Paul Coughlin (Nottinghamshire), Farhaan Berhardien
Outs: George Harding (Released), Ryan Pringle (Released), Will Smith (Retired)
Essex will be pleased to have retained Australians Peter Siddle and Adam Zampa, who were both integral to the club's memorable 2019 season. Ravi Bopara has departed for Sussex, after 18 years in Chelmsford.
Ins: Peter Siddle (Overseas) Adam Zampa (Overseas - Vitality Blast) Moises Henriques (Overseas - Vitality Blast)
Outs: Ravi Bopara (Sussex), Matt Coles (Released)
No new signings so far for Glamorgan but Australian batsman Marnus Labuschagne has re-signed, fresh from his starring role in the Ashes. He scored 1,114 County Championship runs in 10 matches before resuming international duty.
Outs: Jeremy Lawlor (Released), Kazi Szymanski (Released)
Afghanistan leg-spinner Qais Ahmad will be available for the Vitality Blast campaign and the final six County Championship matches. The 19-year-old has played one Test match.
Ins: Jerome Taylor (Overseas) George Scott (Middlesex), Josh Shaw (Yorkshire), Qais Ahmad (Overseas)
Outs: Michael Klinger (Retired), Chris Liddle (Retired), Will Tavare (Retired)
Pakistan international pace bowler Shaheen Afridi has joined Hampshire for the Vitality Blast, whilst Australian off-spinner Nathan Lyon has joined on a red-ball only contract.
Ins: Shaheen Afridi (Overseas - Vitality Blast), Nathan Lyon (Overseas), Scott Currie, Ajeet Dale
Outs: Gareth Berg (Northamptonshire)
Kent signed England U19 leg-spinner Hamidullah Qadri from Derbyshire, as well as Yorkshire batsman Jack Leaning on a three-year contract.
Ins: Matt Henry (Overseas) Mohammad Nabi (Overseas - Vitality Blast) Tim Groenewald (Somerset), Jack Leaning (Yorkshire), Hamidullah Qadri (Derbyshire)
Outs: Mitchell Claydon (Sussex), Adam Riley (Released)
As well as extending Australian all-rounder James Faulkner's stay for a fourth Vitality Blast term, Lancashire signed New Zealand wicketkeeper-batsman BJ Watling for the first nine County Championship matches.
Ins: Luke Wood (Nottinghamshire), BJ Watling (Overseas), Glenn Maxwell (Overseas) James Faulker (Overseas - Vitality Blast), Ed Moulton, Owais Shah
Outs: Haseeb Hameed (Nottinghamshire)
George Rhodes has made his move to Leicestershire permanent on a three-year deal, after initially joining on a short-term loan in 2019.
Ins: Janneman Malan (Overseas) George Rhodes (Worcestershire)
Outs: Aadil Ali (Released), Neil Dexter (Released), Ateeq Javid (Released)
Australian batsman Peter Handscomb has signed a two-year deal with Middlesex, and will take over County Championship and One-Day Cup captaincy duties from Yorkshire-bound Dawid Malan.
Ins: Peter Handscomb (Overseas), Mitch Marsh (Overseas - Vitality Blast), Mujeeb Ur Rahman (Overseas - Vitality Blast), Miguel Cummins, Luke Hollman
Outs: Tom Barber (Nottinghamshire), Dawid Malan (Yorkshire), Ollie Rayner (Released), George Scott (Gloucestershire), Paul Stirling (Ireland)
Kieron Pollard, who has played the most T20 matches in world cricket with 499, will join Northamptonshire in the middle stages of the Vitality Blast. The West Indies captain last featured in the Vitality Blast for Somerset back in 2011.
Ins: Kieron Pollard (Overseas - Vitality Blast), Faheem Ashraf (Overseas - Vitality Blast), Paul Stirling (Ireland) Gareth Berg (Hampshire)
Returning Vitality Blast captain Dan Christian will be joined by a wealth of domestic experience including Peter Trego, who left Somerset after 14 years. Pakistan bowler Mohammad Abbas will be available for the first nine County Championship matches.
Ins: Mohammed Abbas (Overseas) Dan Christian (Overseas - Vitality Blast) Tom Barber (Middlesex), Haseeb Hameed (Lancashire), Peter Trego (Somerset)
Outs: Paul Coughlin (Durham), Nick Kimber (Surrey), Jake Libby (Worcestershire), Luke Wood (Lancashire)
Babar Azam, the leading runs scorer in the 2019 Vitality Blast, will return to Somerset. He'll be joined by experienced internationals Vernon Philander (South Africa) and Matthew Wade (Australia) to replace experienced heads Peter Trego and Marcus Trescothick.
Ins: Vernon Philander, Babar Azam (Overseas), Corey Anderson (Overseas - Vitality Blast)
Outs: Tim Groenewald (Kent), Tim Rouse (Released), Peter Trego (Nottinghamshire), Marcus Trescothick (Retired), Paul van Meekeren (Released)
Hashim Amla signed for Surrey after announcing his international retirement. He'll be joined by three overseas signings including Australia's Michael Neser, who is available for the first half of the County Championship season.
Ins: Hashim Amla, Nick Kimber (Nottinghamshire), James Taylor (Derbyshire), Reece Topley (Sussex), Shadab Khan (Overseas - Vitality Blast) Michael Neser (Overseas), D'Arcy Short (Overseas - Vitality Blast)
Outs: Arun Harinath (Released), Stuart Meaker (Sussex), Freddie van den Bergh (Released)
Sussex have strengthened their bid for a first Vitality Blast title since 2009 with the signings of 2019 winner Ravi Bopara from Essex and Afghanistan leg-spinner Rashid Khan, the number one bowler in the T20 world rankings.
Ins: Ravi Bopara (Essex), Mitchell Claydon (Kent), Stuart Meaker (Surrey), Travis Head (Overseas), Rashid Khan (Overseas - Vitality Blast)
Outs: Michael Burgess (Warwickshire), Abidine Sakande (Released), Reece Topley (Surrey)
Wicketkeeper-batsman Michael Burgess has made his loan move from Sussex permanent, penning a two-year contract.
Ins: Jeetan Patel (Overseas) Chris Green (Overseas - Vitality Blast) Michael Burgess (Sussex)
Outs: Alex Mellor (Released), George Panayi (Released)
As well as retaining New Zealand batsman Hamish Rutherford, Australia batsman Ashton Turner has joined for the club's Vitality Blast campaign.
Ins: Hamish Rutherford (Overseas) Jake Libby (Nottinghamshire), Ashton Turner (Overseas - Vitality Blast)
Outs: George Rhodes (Leicestershire)
England international and former Middlesex captain Dawid Malan replaces Kent-bound Jack Leaning, and off-spinner Ravichandran Ashwin will join after the Indian Premier League.
Ins: Dawid Malan (Middlesex), Ravichandran Ashwin (Overseas) Keshav Maharaj (Overseas), Nicolas Pooran (Overseas - Vitality Blast)
Outs: Bilal Anjam (Released), Karl Carver (Released), Jack Leaning (Kent), Josh Shaw (Gloucestershire), Matthew Taylor (Released)