Natalie Poole, 35, flew to Kyun Pila island on 19 March as a volunteer to help protect a local coral reef.
Ms Poole was originally only meant to stay on the island for one month, but all boat trips to the mainland in Myanmar and to nearby Thailand were cancelled due to both countries being put in lockdown.
Additionally, an evacuation boat that was supposed to rescue Ms Poole was cancelled because Thailand closed its borders.
The volunteer, who has been stranded with four others on Kyun Pila, works as a scuba diving instructor and summer school teacher in Devon.
Since being stranded on the island, her Myanmar visa has expired.
The volunteers have been living with very limited resources and receive sporadic parcels for food.
They have used plastic waste washed up from the beach to set up their camp.
“The hardest thing for me has been not knowing how long we’re going to be here,” Ms Poole told the BBC.
“It’s kind of up and down, we’re a very small group of people and we’re living in a very confined, close situation.”
Ms Poole added that she and the other volunteers are “just trying to take things day by day”.
“We have to be very aware of how much we consume,” she added, “we are eating very basic food and really having to make it last.”