Federer said it was his second visit to the island and he was excited to have another opportunity to get a quokka selfie after he failed in his quest past year.
The tennis champion is in Perth again for the Hopman Cup before defending his Australian Open title in January.
The Swiss great took time to snap some photos with a friendly looking quokka in Australia.
"I thought it was like a bigger mouse, but it's more like a smaller kangaroo", he told reporters.
Shocked to see the all-time great in their midst, the man had to take advantage - even if all he had to sign was a beach umbrella!
The Swiss tennis star said it was his second trip to the island. He never seems to disappoint when posting on his social media either.More news: Watch JAY-Z and Beyoncé's Star-Studded 'Family Feud' Video
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"I've made some adjustments in my game but I think I'm playing very well otherwise I wouldn't be having the results that I'm having". On Thursday, Roger Federer delighted fans by taking a few happy pictures with some quokkas at Australia's Rottnest Island.
Federer had a hit with Aussie favorite Thanasi Kokkinakis, who also is playing the event to get ready for the Australian Open.
While the 36-year-old still enjoys playing tennis and has no plans to retire, it could still be the last chance Perth people will have to see him play live.
"It's totally different this time around", said Federer, whose appearance at the previous edition of the Hopman Cup followed a rare six-month absence as he recovered from injury.
"But the idea past year after I got through all the knee problems was actually to play for the long term, so as long as I'm healthy and happy to play I'll keep doing that".
"Whereas past year, I was like, "Ooh, I hope I'm going to be able to hit my first serves, and I hope it's going to work out as much as it did in the practice".