"So great to come back to this amazing paradise! @visitlordhoweisland #holydaysandfriends @australia," she wrote as her caption.
The couple posed for various photos on the island with friends, which showed them swimming in a crystal clear rock pool, kayaking, hiking and having a general amazing time in paradise.
Hilariously, Chris got in on the fun in a photo he shared to his own Instagram page.
In the shot, the Marvel star, 37, enjoyed a swim in a rockpool, flexing for the photo he pretended Elsa wasn't taking.
"Just one of those truly rare natural moments caught on film where I was completely unaware there was even a camera on me," Chris joked in the caption.
Fans were as expected very flustered by the photo.
"My man be looking ripped without flexing!" wrote on fan.
"Forget Thor, you look like the Hulk!" another wrote, while a third commented: "He's too big to fit in frame!"
The fun holiday comes after the pair celebrated their decade long marriage last month.
They shared a series of shots to social media to mark the occasion.
One throwback showed Elsa beaming as she held onto their three children – India Rose, 8, and their twin sons Sasha and Tristan, 6.