After emerging from the heavily polluted, freezing waters of Manhattan's Hudson River in June it was just days before Ceinwen Roberts and Lisa Delaurentis started planning their next challenge.
Three months on, the Perth open-water swimmers are about to fly to Los Angeles to attempt the 32km Catalina Channel swim.
If successful they will join the elite "triple crown" club, which has just 76 members who have raced around Manhattan Island and crossed the English and Catalina channels.
They faced strong tides in the English Channel and overflowing sewage in the Manhattan waterways, but the Catalina Island to San Pedro journey throws up a new set of challenges.
They will start at midnight to avoid strong winds and to ensure the sun doesn't cast their shadows on to the ocean floor and attract sharks.
"There's a lot of sea life, sharks, whales and dolphins - and kelp, which gets so thick that we might have to crawl over it at some points," Mrs Roberts said.
The swim must also be done individually because there are only two skippers to accompany them.
Over four nights Mrs Roberts, 33, and Ms Delaurentis, 32, and fellow "Swimming Sandgropers" Paul Downie and Wayne Morris, will attempt the journey with just the moon lighting the way, a support boat alongside them and their own thoughts for company.
"You have no one to talk to, nothing to look at, so you very much have to deal with your own thoughts," Mrs Roberts said.Mr Downie and Mr Morris fell short of completing the Manhattan race after strong tides forced them out of the event.