The opening Friday practice for the 2013 Spanish Grand Prix would see rain fall seeing drivers take to the track on intermediates. Pirelli had brought their medium and hard tyres to this event with the hard being more in line with the 2012 tyre. For the Williams F1 team the aim was to carry out a large amount of aero work given the updates that the team had brought to the track but it would not be until late in the session before the track would start to dry seeing both Williams drivers able o run on dry tyres for the first time. As the track started to dry the order changed rapidly with Valtteri Bottas able to move to the top of the times with a 1m:26.456 but quickly he would drop down the times as others improved.

With just minutes remaining Valtteri was fourth while team-mate Pastor Maldonado was down in twelfth, 1m:28.725. Fastest at this point was Massa with a 1m:25.618. As the session came to a close Valtteri was seventh and Pastor fifteenth. Quickest was now Alonso with a 1m:25.252. The times were quite mixed with Vettel and Webber down in nineteenth and twentieth. The Williams team would complete some pit stop practice to end the session. Not a lot could be drawn from the session given the varying track conditions.

Pos Driver         	  Team		        Time     Laps
 1. Fernando Alonso       Ferrari               1m25.252s 20
 2. Felipe Massa          Ferrari               1m25.455s 20
 3. Jean-Eric Vergne      Toro Rosso-Ferrari    1m25.667s 25
 4. Romain Grosjean       Lotus-Renault         1m26.042s 21
 5. Adrian Sutil          Force India-Mercedes  1m26.212s 24
 6. Lewis Hamilton        Mercedes              1m26.374s 19
 7. Valtteri Bottas       Williams-Renault      1m26.456s 20
 8. Kimi Raikkonen        Lotus-Renault         1m26.614s 21
 9. Nico Rosberg          Mercedes              1m26.621s 21
10. Paul di Resta         Force India-Mercedes  1m26.755s 16
11. Daniel Ricciardo      Toro Rosso-Ferrari    1m26.940s 26
12. Nico Hulkenberg       Sauber-Ferrari        1m27.061s 24
13. Sergio Perez          McLaren-Mercedes      1m27.135s 6
14. Esteban Gutierrez     Sauber-Ferrari        1m27.250s 26
15. Pastor Maldonado      Williams-Renault      1m27.576s 24
16. Giedo van der Garde   Caterham-Renault      1m28.600s 19
17. Jules Bianchi         Marussia-Cosworth     1m28.887s 14
18. Heikki Kovalainen     Caterham-Renault      1m29.177s 14
19. Sebastian Vettel      Red Bull-Renault      1m29.457s 11
20. Mark Webber           Red Bull-Renault      1m29.473s 21
21. Rodolfo Gonzalez      Marussia-Cosworth     1m30.314s 12
22. Jenson Button         McLaren-Mercedes      no time   6