Former world triathlon champion Non Stanford is in quarantine at a hotel in Australia after flying to Sydney.
Wales' Stanford, 31, who is engaged to Australian triathlete Aaron Royle, says it "felt like a small miracle" to be able to fly with restrictions affecting worldwide travel.
She says she had three failed attempts to get permission to fly to Australia.
Stanford also says she had to "provide a whole range of intrusive evidence" to show she was engaged to an Australian.
Australian citizens and residents returning from overseas must be quarantined in hotels for 14 days on arrival into the country in a bid to stop the spread of coronavirus.
"Walking into the Australian airport was like walking into the film set of an apocalyptic blockbuster," Stanford wrote in an online blog.
"As soon as we stepped off the plane we were ordered to keep two metres apart from even each other by a bio-masked police officer in surgical gloves.
"Never before could I have imagined this was a reality that we would ever face."
Stanford says she will be unable to leave her hotel room for 14 days and that her room key was taken from her as soon as she had checked in.
"Now I'm not complaining; we are after all in a lovely room with an amazing view of Sydney Harbour and some of the most iconic land marks in the world," she added.
"But as someone put it, it's effectively a luxurious prison cell. The windows don't open and we are not allowed to cross the threshold of the room until our fortnight is up."
Stanford was world champion in 2013 and finished fourth at the Rio Olympics in 2016.
Her career has been hampered by injuries and she underwent knee surgery to remove damaged cartilage at the end of 2019.