The 35-year-old is due to leave the English side of the channel at 10am local time on Sunday (7pm AEST), arriving in Calais about 10 hours and 34km later.

It would be her 35th successful Channel crossing, passing the men's record of 34 held by Briton Kevin Murphy.

McCardel said she will spend less than 10 minutes on French soil and is hoping she will not have to quarantine when she returns to Dover with her support crew later that evening.

It follows an announcement on Thursday evening that people arriving in the UK from France after 4am on Saturday will be required to spend 14 days in self-isolation due to rising numbers of coronavirus cases across the Channel.

"I have made some inquiries about what happens when I get to France," McCardel told the PA news agency.

"Literally, I reach the shore and stand up on land for a couple of minutes, then it's back in the water, swim to the support boat, and head back to England.

"We don't go anywhere near the border officials or passport control, so I'm hoping technically the quarantine thing won't apply.

"I've got a little celebration planned in England with the support crew, the team, the volunteers who have been so supportive throughout this.

"So I am hoping the government allow us to do that without having to quarantine."

McCardel was given special dispensation from Australian authorities to travel to the UK to complete three Channel crossings in recent weeks, taking her level with Murphy.

The Melbourne-raised athlete still has some way to go until she reaches the record of 43 crossings set by English swimmer Alison Streeter.

McCardel holds multiple world records for endurance swimming including the longest unassisted ocean swim, in the Bahamas in 2014.

Australian Associated Press