Maria Kotronakis, 42, from Blacktown NSW, was on holiday with her twin sister, Dimmy, and older sister, Elizabeth, when they decided to go to the Sari Club in Kuta.
But at the last minute, Maria felt a migraine coming on and decided to head back to her villa while her sisters went out dancing.
'The next morning I was woken by a phone call from Mum back home,' Maria told that's life! magazine this week.
Assuming the girls might still be out partying, Maria tried to calm her mother down. But when she switched on the TV, she saw photos of the mass devastation that had killed 202 people, including 88 Australians.
'Rushing to the local police station for information, I was asked to fill out a missing persons report. Next, I headed to the hospital to see whether they'd been taken there,' Maria told that's life! magazine.
'As hours of searching turned into days, reality set in. They weren't coming home.'
Eventually forced to board a flight back to Austrlaia, it was nine days before Maria's family got the call that Elizabeth's body had been found.
Her twin sister, Dimmy, who Maria said she was normally 'joined at the hip' with, was found two weeks later.
'It was the saddest day of my life. It felt like a piece of me had died,' Maria said.
Now, 15 years on from that fateful day, Maria said she has been dedicated to living a life her sisters would be proud of.
She has also found love again with Steven, 41, and is engaged.
'While not a day goes by where I don't think of Dimmy and Elizabeth, I know they wouldn't want me to mourn,' Maria said.
'I know as long as I carry them in my heart, I'll never truly be alone.'