The young lovebirds stopped off for lunch together before heading to a nearby forest for a bush-walking adventure.
Robert and Elisha seemed very happy in each other’s company, laughing and joking while they hung out with Bindi and Chandler.
The couple are said to have met on Instagram after Elisha, who has had a crush on Robert for some time, spent a day at Australia Zoo.
After her visit, the bubbly blonde captioned a snap: “Yesterday I went to Australia Zoo and told @robertirwinphotography how I felt.”
Robert replied: “Thanks for visiting.”
Since then, the pair have had a few flirty exchanges which appear to have resulted in this double date.
And while Robert appears completely smitten by Elisha, there’s no doubt protective Bindi will want to make sure her little brother doesn’t get his heart broken.
She previously shared how Robert, 16, is “one of the best parts” of her life.
“Thanks for being such a great brother. You always remind me to look on the bright side of life,” Bindi shared on Instagram.
Last year Robert was rumoured to be dating Glee actress Emma Perry, while Stranger Things star Millie Bobby Brown also took a keen interest in him.
For more, see this week's New Idea - out now!