Lewis Hamilton is this year bidding to become the second driver in Formula One history to win six world championships.
The 34-year-old Englishman, who last season beat Sebastian Vettel to the title with two rounds to spare, will move to within one of Michael Schumacher's record if he triumphs again this term.
Here, Press Association Sport runs the rule over the 20 drivers who will line up for the season-opening Australian Grand Prix on Sunday.
Mercedes
Lewis Hamilton (Gbr)
Car: 44
Age: 34
Starts: 229
Wins: 73
Championships: 5 (2008, 2014, 2015, 2017, 2018)
Valtteri Bottas (Fin)
Car: 77
Age: 29
Starts: 118
Wins: 3
Hamilton delivered some of the finest performances of his career to clinch a fifth championship last season and lay the foundations for his Mercedes team to win their fifth constructors' title in as many years. The Silver Arrows will face stiff competition from Ferrari in 2019, but Hamilton will start as the favourite to add to his collection of titles. Bottas enters his third campaign for Mercedes, but with his contract up for renewal at the end of the season, the Finn will be under pressure to improve on his middling displays from last year.
Ferrari
Sebastian Vettel (Ger)
Car: 5
Age: 31
Starts: 219
Wins: 52
Championships: 4 (2010, 2011, 2012, 2013)
Charles Leclerc (Mon)
Car: 16
Age: 21
Starts: 21
Wins: 0
Under new management this year, Ferrari will be looking to win their first championship in more than a decade. Both Vettel and his team made a series of mistakes under the weight of Hamilton's mighty performances during the second half of last season, but the Italian team will draw confidence from a promising winter. The highly-rated Leclerc, 21, joins from Sauber and will pose a threat to Vettel's de facto number one status.
Red Bull
Max Verstappen (Ned)
Car: 33
Age: 21
Starts: 81
Wins: 5
Pierre Gasly (Fra)
Car: 10
Age: 23
Starts: 26
Wins: 0
Verstappen will be keen to build on a thoroughly impressive second half of last year and spearhead Red Bull's first assault on either championship since 2013. Following their messy divorce from long-term engine partner Renault, Red Bull will be powered by Honda this season. Young Frenchman Gasly gets his chance to shine after making the step up from Red Bull's junior team, Toro Rosso.
Renault
Nico Hulkenberg (Ger)
Car: 27
Age: 31
Starts: 156
Wins: 0
Daniel Ricciardo (Aus)
Car: 3
Age: 29
Starts: 150
Wins: 7
Following Ricciardo's surprise switch from Red Bull, Renault boast one of the strongest driver pairings on the grid, but will their car be able to match it? The French team have made steady progress since their return to F1 as a standalone manufacturer in 2016, but they will need to take a major stride this season to compete with the top three teams.
Haas
Romain Grosjean (Fra)
Car: 8
Age: 32
Starts: 143
Wins: 0
Kevin Magnussen (Den)
Car: 20
Age: 26
Starts: 81
Wins: 0
The American team are set for their fourth season in the sport and, powered by Ferrari engines, have become consistent midfield runners. Grosjean endured a nightmare opening half of 2018, but suitably recovered to be retained for another year. He is joined once more by Magnussen.
McLaren
Carlos Sainz (Spa)
Car: 55
Age: 24
Starts: 81
Wins: 0
Lando Norris (Gbr)
Car: 4
Age: 19
Starts : 0
McLaren will be desperate to turn over a new leaf following their spectacular demise, and the signs are largely encouraging after a trouble-free pre-season campaign. British novice Norris, and Sainz, who arrives from Renault, form a new-look but inexperienced line-up for the Woking team. Aged only 19, Norris will usurp Jenson Button to become Britain's youngest ever F1 driver in Melbourne later this month.
Racing Point
Sergio Perez (Mex)
Car: 11
Age: 29
Starts: 155
Wins: 0
Lance Stroll (Can)
Car: 18
Age: 20
Starts: 41
Wins: 0
The British-based team have a new name for 2019 following last summer's takeover. Force India is out, and Racing Point is in. Canadian fashion billionaire Lawrence Stroll led the buyout and his son, Lance, has followed him from Williams to race alongside Mexican Perez.
Alfa Romeo
Kimi Raikkonen (Fin)
Car: 7
Age: 39
Starts: 291
Wins: 21
Championships: 1 (2007)
Antonio Giovinazzi (Ita)
Car: 99
Age: 25
Starts: 2
Wins: 0
Famous Italian car manufacturer Alfa Romeo is the second fresh name on the grid after their Sauber takeover. Raikkonen, the 2007 world champion, has joined after he was deemed surplus to requirements at Ferrari. The veteran Finn teams up with Antonio Giovinazzi.
Toro Rosso
Daniil Kvyat (Rus)
Car: 26
Age: 24
Starts: 72
Wins: 0
Alexander Albon (Thai)
Car: 23
Age: 22
Starts: 0
Albon, who was raised in London but races under the Thailand flag, joins the returning Russian Daniil Kvyat for Red Bull's junior outfit, Toro Rosso, this year. Albon finished third, behind British drivers George Russell and Norris, in last season's Formula Two series, the feeder championship to F1. Kvyat's career in F1 looked to be over after he was dropped by Red Bull, and then Toro Rosso, but he has been handed a reprieve after a year on the sidelines.
Williams
Robert Kubica (Pol)
Car: 88
Age: 34
Starts: 76
Wins: 1
George Russell (Gbr)
Car: 63
Age: 21
Starts: 0
Kubica completes one of sport's most remarkable comebacks by returning to the F1 grid eight years on from the rally crash which nearly cost him his life. The Pole will be partnered by F2 champion Russell, of Great Britain, for his grand prix debut. Despite boasting 16 combined driver and team championships, the British team finished last in 2018, and then missed the first two days of winter testing after their car was not ready in time.
