On a day that was sunny Ralf and Marc would spend their day focusing on the new FW26, in preparation for the 2004 season. Nelsinho had the use of a 2003 FW25 to allow him to familiarise himself with the circuit. By the end of the day Marc and Ralf would finish with the third and fourth fastest times respectively.

Ralf would carry out a schedule of set-up work for the FW26, completing seventy eight laps with a best lap time of 1m:15.211. Marc would set a time of  1m:15.131 while working through longer runs with the FW26 looking at sorting out any reliability issues.

For Nelsinho this was his return to the team having tested with them in December 2003. He would complete sixty seven laps with a best lap time of 1m:16.431. He would impress the team with his feedback.

WilliamsF1 Chief Operations Engineer Sam Michael commented on the days testing. He said: "At Barcelona today Ralf spent most of the session working on mechanical set-up while Marc completed long runs for reliability testing of the FW26. Nelson Piquet joined the test to assist with our schedule. Driving the FW25, he spent the day familiarising himself with the circuit and completing some mechanical tests.“

Juan Pablo Montoya will return to testing tomorrow, joining Ralf and Marc. Nelsinho will be back on Thursday.

Pos Driver Team-Engine Tyres Time Laps

1. Sato BAR-Honda (M) 1:13.797 76
2. Alonso Renault (M) 1:14.687 71
3. Gene WilliamsF1 BMW (M) 1:15.129 52
4. R. Schumacher WilliamsF1 BMW (M) 1:15.206 77
5. Button BAR-Honda (M) 1:15.462 26
6. Montagny Renault (M) 1:15.610 63
7. Barrichello Ferrari (B) 1:15.779 69
8. Panis Toyota (M) 1:15.992 79
9. Wurz McLaren-Mercedes (M) 1:16.069 83
10. Piquet WilliamsF1 BMW (M) 1:16.431 67
11. da Matta Toyota (M) 1:16.610 72
12. de la Rosa McLaren-Mercedes (M) 1:16.875 12
13. Fisichella Sauber-Petronas (B) 1:17.016 31
14. Raikkonen McLaren-Mercedes (M) 1:17.315 23