Motor sport's governing body FIA confirmed the proposed switch, with Bahrain taking place at the Sakhir circuit on April 8 and the Chinese GP in Shanghai a week later.
As usual, the F1 season begins with the Australian GP in Melbourne on March 25.
All the other races in the 21-race calendar were confirmed from the original plan set out in June, with the exception of the United States GP in Austin on Oct. 21 being subject to confirmation.
Questions were raised about the Brazilian GP being held next year in Sao Paulo after serious security scares last month.
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Members of Lewis Hamilton's Mercedes team were robbed at gun point in their minivan while leaving the track. Valuables were stolen but there were no injuries reported.
Street crime is endemic in Brazil, which has been battered in the last several years by its worst recession in memory.
Thieves at the F1 race often target cars stuck in traffic jams at the exit of the circuit located about 30 kilometers (20 miles) south of Sao Paulo city center.
In response to these latest incidents, new security measures were proposed Wednesday.
The FIA directly urged that the race promoter uses an "independent security expert to evaluate and advise on security plans," while implementing a police reporting hub at the circuit and improving "overall communication between the promoter security, police and F1 stakeholders."
The French GP, meanwhile, returns after a 10-year absence and will be hosted at the iconic Paul Ricard circuit, also known as Le Castellet, in southern France on June 24.
The German GP, which has struggled with attendances and track fees, was scrapped this year but will return at Hockenheim on July 22.
The Azerbaijan GP has been moved forward to April 29, making it the fourth race of the season. The Russian GP in Sochi, held this year at the end of April, shifts to Sept. 30.
That late September slot was normally reserved for the Malaysian GP, which has been dropped.
2018 schedule:
March 25: Melbourne, Australia
April 8: Sakhir, Bahrain
April 15: Shanghai, China
April 29: Baku, Azerbaijan
May 13: Barcelona, Spain
May 27: Monaco
June 10: Montreal, Canada
June 24: Le Castellet, France
July 1: Spielberg, Austria
July 8: Silverstone, England
July 22: Hockenheim, Germany
July 29: Budapest, Hungary
Aug. 26: Spa-Francorchamps, Belgium
Sept. 2: Monza, Italy
Sept. 16: Singapore
Sept. 30: Sochi, Russia
Oct. 7: Suzuka, Japan
Oct. 21: Austin, United States (asterisk) (subject to confirmation)
Oct. 28: Mexico City, Mexico
Nov. 25: Abu Dhabi, United Arab Emirates.