With the deadline for registering for a postal vote now passed, this is the final opportunity for overseas voters to take part in the once-in-a-generation vote.
With less than a month to go until the referendum, the British Embassy in Vienna told The Local Austria they have been receiving “lots of phonecalls” from people concerned about what would happen to them if Britain were to vote to leave.
“It's not clear,” Ambassador Susan le Jeune d'Allegeershecque said. “As David Cameron has said, it really is a leap into the unknown.”
Asked whether they were making preparations for what to do in the scenario that Britain votes to leave, she said they weren't and had not received any instructions from Westminster.
Due to voters registering with their local constituencies in the UK, officials in Vienna do not know how many of the 9,000 British people living in Austria have registered to vote.
In general elections, turnout from overseas voters is typically low but embassy spokesperson Lukas Wiesboeck said that based on the number of calls they have been receiving, they expect it to be higher in the referendum.
"Anecdotal evidence suggests that there will be more than in the national election," he said.
Britain's voice at the UN
As the UK Permanent Representative to the United Nations, le Jeune d'Allegeershecque has also voiced concerns over how leaving the EU could impact on Britain's position at the UN.
“When we sit down at the UN as part of the EU 28, our voice is much greater. If were were to leave, the chance for getting British views reflected would be difficult,” she said.
“Now is not the time to be isolationist. It's risky to think that with problems like climate change, terrorism and competition, we'd do better dealing with them on our own.”
"I am optimistic. I don't think we will leave. I think - I hope - the British people will vote based on the hard facts."