A video posted online during his stay showed him embracing Aussie culture, donning a pair of thongs, a singlet, sporting a mo', and a mullet.
In Bahrain, he's taken that a step further with his 2023 pre-season testing helmet showcasing his new hairstyle.
“I'm so proud of my new look so I thought it would need to be painted on a helmet,” Bottas said on Twitter.
Speaking to the media on Thursday, he added: “I thought why not have my face painted around my face to keep things fun.
“It's important to do that, to not take some things too seriously. I like it.”
Bottas also leaned into the ‘Australian' style. Referring to the mullet, he said: “For now it's staying. I'm really proud of it.
“There are no intentions [of getting rid of it]. Feels very much part of me!”
Since joining Alfa Romeo at the beginning of 2022, Bottas has allowed more of his personality to shine through.
The 33-year-old has grown in popularity as a result, especially among Australian fans.
He has also established himself as a capable team leader – he scored 49 of Alfa Romeo's 55 points with a best finish of fifth in the Emilia Romagna Grand Prix last year.
The bulk of his points-paying results came in the opening half of the campaign before the squad fell behind in the development race.
Hopes are therefore cautiously optimistic heading into the new season.
Bottas delighted by improved Alfa
Following a solid opening day of the three-day test at the Bahrain International Circuit, Bottas completed 71 laps and team-mate Zhou Guanyu 67.
“The car feels good,” said Bottas. “I can clearly feel some improvements to last year.
“What is, I would say, the main positive is that we didn't have a single issue, which is a huge contrast to testing last year, so at least we have started on the right foot and done some proper mileage, which is at this point, so important.”
Detailing the improvements, he added: “The rear of the car has become more stable, which was a weakness last year, especially in the higher-speed corners, so that's good.
“But we still need to fine-tune the balance, especially in the slower speed, and I'm struggling a bit with locking up the fronts and understeer, but nothing that we can't solve.”
Pre-season testing continues in Bahrain on Friday and Saturday ahead of the opening race of the year at the same circuit next weekend.