This is the best time to visit Rottnest Island - for the ultimate quokka experience

I'm in a battle with a quokka and I'm not smiling. It, on the other hand, looks as happy as they always do.

The sun has gone down over the Indian Ocean and Rottnest Island is dark, so I've headed to the pub for dinner. Settling in with a pizza at a peaceful outside seat, I find this quokka has other ideas, jumping up, trying to grab a slice. "Shoo, shoo!" I wave my hands in vain, but it's not scared. A waiter walks over and just pushes it off the table, obviously used to this behaviour. But it'll be back. I know.

Spending the night here on the island, just off the coast of Perth, gives me time to get to know these mischievous marsupials. The quokkas are the main attraction of Rottnest Island and hundreds of day-trippers arrive every morning to see them. The irony is that they're generally nocturnal and only a handful will appear before it's time to get back on the boat.

Before dinner, as an orange glow filled the sky, a couple of quokkas emerged right in front of me as I sat having a beer on the oceanfront balcony of my glamping tent at Discovery Resorts. But it was as I strolled to the pub, through the main town's lawned centre, that I suddenly saw hundreds of them - munching on the grass, and hopping across the footpath where I was trying to walk. Are these cute Rottnest Island icons really just pizza-stealing trip hazards? Surely not!

Although the quokkas may have become the (grinning) face of Rottnest Island, they are mainly concentrated around the town and there's plenty more to discover when you give yourself a bit of extra time. With one SeaLink ferry a day from central Perth and up to 10 from nearby Fremantle, there's lots of flexibility to arrange your visit for as long as you like. I've given myself about 24 hours, so I hire a bike first thing in the morning and set off to see as much as possible.

"It can feel like you are crossing continents when you traverse the island landscape," the tourism brochure says. Although it's referring to the six unique ecosystems you'll find here, my legs start to feel like they're crossing actual continents. Rottnest Island is much bigger than I realised, the main road loop about 22 kilometres long and with lots of hills. I now see why all the e-bikes had sold out.

The south coast, where I start, is rugged, rocks pockmarked by the wear of waves, yet the sparklingly clear water reveals thriving coral just below the surface. On the other hand, the north coast is quieter, with gleaming stretches of white sand in protected bays. This is where most people go to swim but, with more than 60 beaches on the island, there's no shortage of variety to choose from. It would be easy just to spend the whole day swimming and snorkelling at a few of them.

Instead, I continue on the bike, past colourful flowers blooming among the scrub heath, right to the furthest tip at West End, where a coffee cart appears like an oasis. Here, an elevated boardwalk weaves over the protected habitat to a viewpoint where you'll sometimes spot long-nosed fur seals on the rocks. From its own viewpoint atop a pole, an osprey keeps an eye on everyone.

Across the width of just one small (if you don't ask my cycled-out legs) island, the breadth of wildlife is remarkable - in the undulating sand dunes, around the large salt lakes and their wetlands, and in the shade of tea-tree woodlands. But dotted through it all are opportunities to discover the human heritage as well.

Named for the local Noongar word for the island, the Wadjemup Museum has a focus on the story of thousands of Indigenous people who were incarcerated here until 1931 and how it "continues to impact Aboriginal people across Western Australia to this day".

There are also exhibitions about the military and maritime history, although you can explore both those things in the centre of the island, at the white-painted Wadjemup Lighthouse towering 38 metres high, or the large naval gun battery at Oliver Hill that was built in 1937 to protect Fremantle Port.

I'm starting to think even 24 hours isn't enough. Rottnest Island seems like a holiday destination in itself, not just a day trip from the mainland. I haven't even tackled any of the hiking trails, let alone looked at the tours, boat trips or golf course (not that I can play). I also want to fit in some time to relax at my accommodation at Discovery Resorts.

The resort has about six types of tents spread among the trees, although this is definitely glamping not camping, with comfortable beds, ensuite bathrooms and kitchenettes. I'm in a deluxe oceanside tent, boasting gorgeous views across the turquoise water. It's tempting just to wander across the small dunes for a swim, but the resort also has its own pool right next to the restaurant and bar so, if you are here for a holiday, a cocktail and a dip could be perfect after a day of cycling.

Not that it's all relaxation here at Discovery Resorts. The first time I go into reception, I have to let myself in through a waist-high gate. I ask a staff member whether it's to keep the children in, so they don't wander off into the wilderness. "No, it's to keep the quokkas out," she laughs. "Although they're pretty smart so they'll work it out one day."

I told you! It's not all smiles with these cheeky little critters!

The writer was a guest of SeaLink and Discovery Resorts