You must trust your partner,” says our spitfire-quick South African yoga instructor, Tamara. This is how our “acro” — as in acrobatic — yoga session starts. Laying out mats on a lawn of spiky Caribbean grass, she has us on our backs in a flash, looking up at a Tiffany blue sky. A marshmallow cloud may float by, but who needs perfect? With the breeziest and briefest of demonstrations, she talks us into a puzzle ring of appendages, a human Turk’s knot. It wasn’t until after I’d piked off my acro-partner’s back, supported her aerial Superman pose and various other contortions that I got it. You have to be calm, not just strong, precise in how you hold yourself and, yes, trusting.

It’s a dynamic that works for us. We are sisters-in-law, close in age, bound by family as well as shared creative pursuits. Taking a break for a few days last spring, we want to stretch and energize more than just our pale winter bodies; we’ve been talking about writing a book. We are readers, writers, wordy girls, both of us engaged professionally and passionately, on some level, with the development and creation of narrative. And as the product of matriarchies, we are also fascinated by the female characters in our families who came before. Who were these women of the 20th century who shaped us? What were their lives like? As much as we’ve learned from our own mothers, we have questions and, of course, time is of the essence. While the concept might still be abstract — part memoir, part history — our intentions are real, and where better to engage creatively than at a much-loved island retreat in a generations-old family house?

Tiny Harbour Island lies a mile or so off the tip of North Eleuthera in the Bahamas. It’s just a short hop from Nassau but feels a world away. In the 1960s, my sister-in-law’s intrepid grandparents bought property here. Three miles long with a beach the colour of Himalayan pink salt ground to a fine powder, its narrow laneways and overgrown gardens are a riot of fuchsia bougainvillea. Briland, as it’s called locally, is a bit of magic. No airstrip, no golf course, not many cars and, at its centre, colonial Dunmore town, settled in the 1700s. I am aware that as creative processes go, this one is well supported, not just in acro-yoga terms but also by good fortune.

I came here first as a teenager. Remarkably, in a six-degrees-of-separation kind of way, one Christmas in the 1970s, while Sarah, my sister-in-law, was at her family’s house on the bay side of the island, my siblings, cousins and I were running wild just down the beach. Our family had converged on Pink Sands Lodge (as it was once called) – back then, an unfussy, faded chintz and wicker-laden resort, the kind you don’t see here anymore — to celebrate our grandparents’ 50th wedding anniversary. My brother, 11 at the time, likely would’ve scowled adolescent-style if you’d suggested to him that his future wife was close at hand.

Over the years, Harbour Island kept calling me back. In my 20s, one friend bought a ramshackle old house in town; later, another bought property on the beach. There were tanning trips, writing trips and boyfriend trips and, eventually, by the time Sarah and my brother took over her mother’s house, I had come often enough to feel a comfortable familiarity. There’s also a psychic connection. Walking the beach one day, a memory is jostled to consciousness, I reach through time and conjure my grandmother, gone more than 20 years, who loved it there. For Sarah, third-generation on the island, the layers of memories and experience are all the richer and deeper still. This island is like a sensory memory bank.

Morning comes early on Harbour Island as free-roaming roosters, glossy-headed and entitled, start crowing well before dawn. This has its advantages. We are up and out before the sun gets too hot and the tide too high. Just a few minutes’ walk from the house toward the ocean side of the island, we arrive at the top of Alice Street and the path to the beach that snakes down the dune through dense tropical foliage. Already, we feel the sun, even if it’s still low on the horizon. Tucking our flip-flops under the brush, we head south, our footprints embossing the sand then disappearing in the foamy rush of waves.

The light on the ocean, at this hour especially, has a magnetic allure.

We are talkers, our dialogue a constant exchange of observations, exclamations, non sequiturs – and not exactly linear. As we walk, we survey the oceanfront houses built on the dunes until the hotel properties begin, announced by clusters of umbrellas and chaises. Runaway Hill, Coral Sands, Oceanview: low profile in both height and style, their particular shades and contours speak to me. But it’s Pink Sands, the scene of my youth, that pulls me in the most. Its beach bar, now painted periwinkle blue, reminds me of being 15, free on the island, my first real camera in hand and a crush on a boy I’d code-named Specs.

On our return walk that day, we encounter a woman who has set up her easel to paint a beach scene. We stop to talk, and eventually her husband, also a painter, comes along the beach. A random exchange with strangers about painting, writing, Paris, Walmart, James Taylor, The New Yorker, Susan Orlean and inspiration. It felt like a kick-start. There’s nothing that jacks my creativity more than escape from routine, and these beach walks prove the point: far from nagging reality, ideas pop up, and sentences write themselves inside my head.

After a swim, we have breakfast on the terrace, and the day falls naturally into place around reading, exercise and meals. In the afternoons, there are errands, both necessary (groceries) and not (the shops, so seductive). In fact, seduction is everywhere on this island, palpable in its humanity and natural beauty, its colonial facades painted gelato hues, its stores named with impressive specificity (Dis and Dat being my favourite) and, when school lets out, the island children in their neat navy blue tunics and white shirts bursting with energy, smiles and infectious laughter.

Then it’s on to cocktails. In years past, a much-loved and now lamented sundown ritual on Harbour Island was a drink at the Pink Sands Lounge, a modest bayside bar facing west toward the government dock. As low-key as it was, it was also a scene, its terrace the only place to be at 6 p.m. for the nightly sunset theatrics over Eleuthera. Dark glasses were de rigeur, and teenagers could reliably count on the presiding bartenders – island institutions – for their first underage Goombay Smash. In those long ago, pre-celebrity days on the island, before Elle Macpherson and Diane von Furstenberg and company arrived, the Pink Sands Lounge was my idea of glamour.

Of course, there’s no shortage of spots on the island for drinks ranging across the full high-low spectrum. Unquestionably at the high end is The Dunmore, a hotel where we land one evening. Its tiny classic lobby bar is atmospheric, framed by old-fashioned jalousie windows, but it’s the collection of vintage black and white photos of Harbour Island lining the walls of the restaurant that really sets the vibe. Evocative of a seemingly less complicated era — grainy scenes of fishing boats, barefoot children, ladies in long dress — the images launch us into a conversation that takes us well into dinner about life in our respective grandparents’ time, whether on a tiny Caribbean island or continents — and even hemispheres — away.

After dinner, we head home where, conveniently, literary inspiration is always within reach, regardless of whether you’ve packed a book or not. Several generations have filled the shelves of the house, the library now a barometer of the age, tastes and political inclinations of guests in decades gone by. From heavy faded tomes like Fishes of the Bahamas and Adjacent Tropical Waters to Arthur M. Schlesinger’s A Thousand Days: JFK in the White House to Joan Didion’s The Year of Magical Thinking, we’re covered.

On our last night, we face reality: we’ve talked around our book project for days, but we haven’t written or recorded a thing. We can’t leave with nothing to show for our enthusiasm so we make notes, a rough plan and commit to a timeline. As much as a setting can inspire, we know what it takes to lasso one’s musings and put them to work. Were we overreaching here on Harbour Island? Can we store up inspiration as we do vitamin D from the sun’s rays? Can we apply it like aloe vera gel on a sunburn once we’ve returned home to the north? I think so. But what really inspires and motivates most is each other’s interest and engagement. We’ve started at least. So we’ll call it what it is: one more precious interlude here to add to the memory bank, a partnership sealed in acro-yoga and, since the book is a reflection on family, the island strengthens our connective tissue, even becoming our muse.

What inspires me may not register with you, but it’s hard to imagine anyone spending time on Harbour Island and not being touched by it.

Here are a few of my favourite things.

The beach Run or walk barefoot the length of Harbour Island’s luminous pink beach at low tide when the sand is firm yet forgiving, the sunlight glimmering on the ocean water, then tell me you’re not inspired.

Queen Conch Yes, it’s overly chewy and won’t necessarily meet a visiting gastronome’s standards, but conch salad tastes like the Caribbean Sea to me, and Queen Conch is where I must eat it. A little roadside “café” – that’s generous – overlooking the harbour is the real deal and inspires my tastebuds without fail.

Miss Mae’s I never get sunset fatigue, but if ever I need an infusion of man-made beauty, I go to Miss Mae’s in the centre of town. Exquisite pieces, accessories and objets, the shop is like a curated tableau of good taste, thanks to Miss Mae’s owner, Pip Simmons, who also built Oceanview, everyboy’s favourite hotel if they have any taste at all. Not just inspiring – inspired.

The “jump up” church Of all the (many) houses of worship on Harbour Island, perhaps the most notable is the “jump up” church where residents and visitors alike get in on the evangelical action and, well, jump up. It’s a draw for the music, but if you’re at all religiously inclined, it’s bound to get you going.

Gusty’s I can always count on Gusty’s, a much-loved island bar for nocturnal inspiration because what’s better than late-night beers and dancing to Bob Marley under the stars? Plus, I think my muse hangs out there.