The two in-season tests are set to take place after the Spanish and Hungarian Grand Prix during the 2018 Formula 1 season.
The Circuit de Barcelona-Catalunya looks set to host the first two-day test on the Tuesday and Wednesday following the Spanish race next May, while the Hungaroring looks set to host the second test on 31 July-1 August 2018.
According to Motorsport.com, those two venues will be the chosen ones for the tests, with Barcelona coming in to replace the Bahrain International Circuit that hosted one of the tests in 2017, while the Hungaroring will continue for a second consecutive season.
Spain last hosted an in-season test in 2016, where Silverstone was the other venue, while teams will again be mandated to use young drivers for at least two days of the four.
A request was made for Paul Ricard, which returns to the calendar in 2018 for the first time since 1990, to hold a test, but this has not come to fruition, although it could still host some Pirelli tyre tests, which will continue into next season, particularly as it offers the chance of wet weather testing thanks to its track watering system.