Day 4 of the 2026 Barcelona shakedown took place behind closed doors at the Circuit de Barcelona-Catalunya, once again with limited official information available. Nevertheless, more cars were active on track compared to previous day, and several teams moved forward with more advanced programmes.

The main storyline of the day was the first appearance of the Aston Martin AMR26. After arriving late to the circuit earlier in the week, the team finally sent its new car out in the afternoon session. The AMR26 completed installation laps before returning to the garage.

Mercedes remained the reference point on Thursday. George Russell set the fastest lap of the day with a 1:16.641 on soft tyres (according to the SoyMotor website). According to paddock indications, Mercedes has already begun experimenting with more performance-oriented runs, underlining the team’s smooth start to the new regulations cycle. Earlier in the day, Andrea Kimi Antonelli completed a high mileage programme, continuing Mercedes’ emphasis on both reliability and pace.

Ferrari also maintained steady progress. Charles Leclerc was active throughout the afternoon, gradually improving his lap times but without chasing outright performance.

McLaren joined the action again with Oscar Piastri, following Lando Norris’ earlier running in the week. The team was forced to end running earlier due to a fuel system issue.

Cadillac continued to add mileage with Sergio Pérez returning to the cockpit in the afternoon, while Racing Bulls and Mercedes remained among the most active teams overall.