Mercedes again set the pace in Barcelona led by Lewis Hamilton, but Max Verstappen was close to the Black Arrows on the long run programmes.
They were again head and shoulders above the rest of the field in qualifying sims though, Hamilton was eight tenths ahead of third-placed Verstappen.
Bottas was a third of a second behind his teammate, in yet another Mercedes 1-2 after the Finn dropped to third in the championship last week behind Verstappen.
Romain Grosjean had another good session to finish fifth, the Frenchman looking revitalised and confident after a tough start to the season.
He’s yet to score a point in the championship but his form looks to be on the rise following his 13th in qualifying last week and sixth in FP1 this morning.
It’s his best practice session since Australia last year when he placed fourth in FP3, although he didn’t score in the race due to a pitstop issue after running comfortably in the points.
In fourth was Daniel Ricciardo, a vast improvement from his morning running when he was a lowly 18th.
Charles Leclerc was sixth as he continues to impress for Ferrari and the Monegasque was only 0.014s behind Grosjean.
Sebastian Vettel continued to struggle in the other Scuderia though, despite a new chassis this weekend he was twelfth, a quarter of a second behind his teammate.
Carlos Sainz was seventh at his home race after running out of the top ten in FP1 ahead of Sergio Perez, Esteban Ocon and Pierre Gasly.
Perez has fitted seamlessly back into the RP20 and is already outperforming Lance Stroll, who placed eleventh behind Gasly.
The AlphaTauri driver continued his run of form by reaching the top ten and was only a hundredth of a second behind his compatriot, Ocon struggling early on with the car pulling to the right under braking.
George Russell took the car for the first time this weekend after Roy Nissany sat in for FP1, the Brit found the car balance difficult, and placed last.