The session was interrupted with a red flag to clear oil dropped on the track in several places by the no67 Ford GT of Harry Tincknell.
Mike Conway led the way in the no7 TS050 with a 1m42.313 lap, 0.199 seconds ahead of the no8 Toyota with Sebastien Buemi posting a 1m42.512. The no1 Porsche was the faster of the two 919s in the last WEC weekend for the German manufacturer. Neel Jani set a 1m42.647, 0.166s ahead of the 2017 champion Timo Bernhard in the no2 Porsche.
The no51 AF Corse Ferrari was the quickest of the contenders for the remaining FIA World Championship still be decided in Bahrain. Championship leader Alessandro Pier Guidi set the fastest lap in the LMGTE Pro category, the Italian posting a 1m58.579, 0.322 ahead of the no97 Aston Martin Vantage of Jonny Adam. The no67 Ford GT of Harry Tincknell had returned to the pits after causing the red flag by dropping oil on track. The mechanics got the car ready and the English driver returned to the track to record the third quickest time, a 1m59.413, 0.8s behind the leading Ferrari.
The LMP2 category was headed by the no13 Vaillante Rebellion Oreca of Nelson Piquet Jnr with a 1m48.707, just 0.022s ahead of Loic Duval in the no26 G Drive Racing Oreca, the 2013 FIA World Endurance Driver’s Champion making his LMP2 debut this weekend. The two LMP2 championship contenders could only manage 7th and 9th fastest in class with the no38 Jackie Chan DC Racing Oreca posting a 1m49.854, 1.1 seconds behind the fastest in class. The championship leading no31 Vaillante Rebellion Oreca was 9th and slowest in the LMP2 category with a best lap of 1m50.467, 1.7 seconds behind their teammates.
The LMGTE Am class was headed by the no77 Dempsey-Proton Racing Porsche, with Matteo Cairoli posting a 2m.00.428 lap, 0.125s ahead of Pedro Lamy in the championship leading no98 Aston Martin Racing Vantage.
The second Free Practice session will take place under the circuit floodlights and under the stars in the desert. The 90-minute session is due to get underway at 19:30 local / 17:30 CET.