The group were found alive on a deserted island by rangers on Saturday after they were missing for over 40 hours.
Nevalainen and her fellow divers, three Britons and a Frenchman, were swept away in strong currents on Thursday afternoon.
“It was an extremely strong current, extremely powerful. We weren’t able to do anything other than follow it,” she told news agency TT.
How did you survive?
“People are capable of more than they think. We had more or less nothing to eat and absolutely nothing to drink.
“We tried to sit in the shade and wave at passing boats.”
How did you help each other?
“We sat and talked. Sometimes we sat on our own. One felt quite… alone. We were gone for 44 hours after all. I just hoped a boat would come and get us.”
Nevalainen said the group feared for their lives in the unbearable heat.
“All sorts of thoughts went through my head. All sorts. We just hoped we’d be saved when the sun went up.”
Waving from the shoreline of the tiny island of Rinca, the divers were finally rescued by local rangers.
“We were completely overwhelmed. So happy we just cried. Everyone was just crying.
“I’ve never had a happier moment in my life. We thought: ‘we’re not going to survive another night without water’. It was so incredibly hot despite sitting in the shade.”
Once the divers had been found, the Indonesian coast guard sent out a motor boat to bring the divers back to dry land, where Nevalainen was reunited with her boyfriend Mats Köhler.
“I’ve only been able to sleep a few hours since Helena went missing,” said Köhler.
“I’m completely exhausted but everything has worked out well.”
Mats Köhler was full of praise for the local population.
“We’ve received tremendous amounts of help from the diving centre and the whole village has helped out. It’s the most touching thing I’ve ever seen in my life.
“They really cared and were out searching with their boats. The local populace has got involved in a fantastic manner,” he said.
The divers endured two nights on the deserted eastern island which is infested with the huge monitor known as komodo dragons.
Laurent Pinel, 31, told AFP the group had to fight off one dragon with rocks and scavenged for shellfish as they waited to be rescued from the tiny island in the Komodo National Park, east of Bali.
“On the beach a komodo dragon came amongst us yesterday (Friday) afternoon,” the Frenchman said, describing how the group had to pelt the dangerous reptile with rocks to scare it away.
“We had nothing to eat. We ate some kind of mussels scraped from the rocks,” Pinel told AFP from a medical clinic in this sleepy port on Flores island where the divers were being treated after their rescue.
The Parisian said the divers had spent about nine hours adrift at sea late on Thursday after being swept away from their dive boat in one of the strong currents for which the area is notorious.
They struggled against the rip to reach islands they could see in the distance but after several hours they stopped swimming and tied themselves together by their diving vests to preserve energy.
Late on Thursday night they saw another island and decided to make one more effort to reach land, fearing they would be carried out of the relative protection of the Nusa Tenggara island chain and into the open sea.
“If we’d continued (to drift), it would have been the ocean,” he said.
“We were exhausted. Everyone had cramps.”
What they did not know was that they were heading to Rinca Island, a reserve for aggressive komodo dragons that can easily kill a human.
The largest lizard in the world, komodos usually feast in packs and can easily devour prey as large as buffalos. One bite can be extremely dangerous due to the virulent bacteria in their saliva.
Helena Nevalainen had returned from a medical clinic and was still registered at a hotel in Labuhan Bajo and, AFP reported on Sunday morning.