The trio was photographed together on Wednesday in Australia's Byron Bay, where Chris, 36, and his wife, Elsa Pataky, 43, have famously settled down to raise their family.
Brooks tanned on a towel as she watched the two brothers catch some waves.
Liam, 30, and Brooks, 23, were first spotted together in December for a brunch with his parents, Craig and Leonie, in Byron Bay.
Since then, the two have been spotted out together frequently, kissing on a beach in Australia, enjoying casual dates in Malibu and basking in quiet nights at home playing Scrabble games while staying in amid the coronavirus pandemic.
Earlier this month, Liam told PEOPLE he was happy to be back in Australia near his family.
Media-Mode/SplashNews.com Liam and Chris Hemsworth with Gabriella Brooks
"It's just a very mellow area where I grew up," he told PEOPLE. "It's quiet and it's a beautiful spot. I'm able to see the ocean from my house."
Liam, an avid surfer, has also found moments of bliss out on the water. "You're still allowed to surf here. I paddled out the other day and it was just a really beautiful day and the surf was good and I was on my own," he recalled. "I'm just grateful to spend time here right now."
Even playing Scrabble with Brooks has "made me nostalgic and brought back memories," he said.
"I used to play with my grandma when I was a kid. She loved Scrabble," he said. It also made him realize "that I'm terrible at spelling," he added, laughing. "I was cheating and Googling words."