Video report by ITV News Scotland Correspondent Peter Smith
There are no Intensive Care Unit (ICU) beds with ventilators on the islands, it's a long, long way to the nearest hospital, and any medical evacuation to the mainland could be weather-dependent.
This week the NHS Western Isles health board reported its first Covid-19 cases. Three elderly patients based on the Isle of Lewis - and apparently not connected - have now tested positive.
That's not to say there aren't more cases - people just aren't being tested on any kind of meaningful scale on the islands.
The remoteness of the islands has been construed as a kind of strength that could shield these communities from the worst of coronavirus. Now the virus is in, though, that remoteness reveals a weakness when it comes to treating patients.
The Isle of Barra, for example, uses a beach as an airport runway which makes medical evacuations more complicated. The school and the village hall also had to be converted to makeshift Covid-19 hospitals, to ensure the island's main hospital is kept virus-free.
I spoke to the island doctor, Mark Willcox, who told me the island is trying its best to prepare. He said: "Even at the best of times, getting medicines here is weather-dependent.
"So if we suddenly had a huge influx of people requiring that kind of assistance then I can see how we would find ourselves stretched very thin, very quickly."
On the neighbouring Isle of Coll, the island has an elderly population, and only one doctor working with extremely limited resources in terms of Personal Protective Equipment (PPE).
Coll's Dr Celine O'Neill published an open letter to all residents last week explaining how exposed their island could be.
"There is currently no immediate MediVac capability as the medical helicopter is not suitable, and although the fixed wing air ambulance is an option for [other islands], it is not a possibility for Coll airport due to its short runway," she wrote.
"This message is to inform you of the extreme fragility of our island community in relation to the coronavirus."
Since then, Dr O'Neill has worked tirelessly to ensure the situation improved for her community. She told me she has secured more PPE and has since been told there is now an option for Coll to have sick islanders taken to the mainland in an emergency.
"We are now assured there is a bespoke solution in place to facilitate isolated transfer of critically ill Covid-19 positive, or suspected, patients from the Isle of Coll to the receiving hospital," she said.
"The situation is always changing but I'm in regular communication with the emergency medical retrieval service and the Scottish Ambulance Service who are committed to supporting our community."
Her efforts could save lives and it has certainly reassured the people on the island to know they're not cut off.
Another area of vulnerability on Coll is that the island only has one shop.
Having everyone on Coll going to the same place for essential supplies could be hot spot for infection, though. And so the community adapted.
Pictures of items on the shop's shelf are now posted on Facebook, shopping lists from the residents are emailed in, and the two shop keepers, Dougie and Paula, make up the orders. Then, during his downtime, the island's postman, John, delivers the shopping door-to-door.
No one has to leave the house, and everyone gets what they need. It is island innovation for isolation.
Islanders are also not as far removed from the global pandemic as it may seem. Ballyhaugh, on Coll, is home to the international charity, Project Trust.
They had 200 volunteers in 19 countries and when coronavirus started taking hold - all of them had to be repatriated.
This was a major global operation at the best of times. The fact it was co-ordinated from a Hebridean island, in lockdown, with limited internet connectivity is testament to the resourcefulness of islanders.
This is key to island life.
These are communities that know how to cope when supplies don't arrive on time, when harsh winters cut them off from the mainland for weeks, and where looking out for neighbours isn't a novelty.
Being resilient is just a way of life in the Hebrides.
In the months ahead, that could make all the difference.
Coronavirus: Everything you need to know