In the winter, they are largely marooned, the conditions too hazardous for the four-mile boat journey to the main island. Their neighbour, who spends summers away fishing or skippering, is a 20-minute walk away.
Sometimes the couple drop in to see him, deliver his mail - which they row to collect - and share their news, if there is any, but broadly life on Soay is a life shared by just the two of them.
“Our relationship is extra stong,” says Anne. “That has been one of the reasons we have manage to live happily together in such an isolated environment.
“We are both passionate about the same sorts of things. We both love wildlife and like to have animals around us. We both fell in love with the island before each other to begin with.
“We have not needed space from each other for 15 years,” she adds, checking with Robert that this is the case. It is the case, he agrees.
Of similar temperaments, Anne says they trust each other to do what is necessary to survive on the island. While Anne hates heights, Robert is like a “monkey”. While he hates small dinghies, Anne loves hitting the water and rowing.
Soay has a fairly industrious past and was home to shark hunter Author Gavin Maxwell, of Ring of Bright Water, who set up a shark fishing station here after the war. Former soldier and adventurer Tex Geddes took over the business.
When Anne, 55, arrived on Soay in 1990, there were 17 people living there, including Tex, who died in 1998, and his wife Jeanne.
Many changes have washed over Soay in time, lights have gone out in properties and departures made. But Anne and Robert, 64, remain, and have no intention of leaving.
Anne was working in London when she decided to move to Soay. Working as a graphic designer,including a spell at Saatchi and Saatchi, her social life the typical city mix of dinners, theatre and bars.
But a feeling of “discontent and dissatisfaction” could not be shaken. There was no real challenge or excitement, says Anne, and the wild nature she craved seemed very far away.
A holiday to Skye in 1989 changed it all, a house for sale in the window of a Portree estate agent seemingly having the answer.
Six words on the schedule latched on to her: “access by courtesy of fishing boat”.
Within a matter of months, her cottage in Bedfordshire was sold and she was now the owner of Glenfield House on Soay, a three-bedroom place with no electricity.
A year after her move, the Royal Marines, on a training exercise around Soay, agreed to airlift her upright piano from the main island using a Sea King helicopter.
Robert, originally from Devon, was part of the team involved in the operation. He revisited Soay many times after that, buying a house on Soay in 1998. The couple married in 2005.
Life on Soay is most definitely not about “drinking tea, looking at the view all day,” Anne says, who describes the huge physical effort required to live on an island with no infrastructure.
There are livestock to care for, a boat to maintain or a rotten window to fix.
Food shopping is done once a month in Broadford during the summer months. The day-long mission starts with a four mile boat trip to Elgol, a short row ashore and then a 15-mile drive to the town. Three trolley loads of good are packed into waterproof sacks and plastic boxes and taken home on the boat again.
Three tonnes of coal are shifted this way every year and by autumn, the pantry is “wall-to wall” tins and dried food. A constant supply of spare parts, tools, screws, nails are required and nothing is generally thrown away.
“There is a very satisfying feeling when all the necessities of life are safely gathered in,” Anne adds.
Winkle picking provided Anne, an artist, a small income for many years, with the couple now able to survive on the modest Ministry of Defence pension of Robert, who also works as a sculptor.
Depsite the endurance required for Soay living, the rewards are ample for the couple, whose family usually come to visit in the summer.
A herring gull they nursed as a sick chick now lives on their chimney pot and knocks three times a day for food. The sight of an otter trying to eat a crab on the beach or a pod of dolphins leaping in the bay by their house makes them feel like they have it all.
“There are very many things that make us smile,” Anne says.
“Time is dictated by the seasons, the weather and the tides, In my old life my time was dicated by the clock, deadlines and the weekend.
“I can honestly say that neither of us every get a deep need to leave the island. If anything we get a deep need to get back to Soay if either of us is away for too long.”
Island on the Edge, A Life on Soay by Anne Cholawo is published by Birlinn.