"It would have been horrific for the two women at the time, which would have happened so quickly; in total darkness; in silence of the early morning; and in an environment of an upside down car fully submerged during a full tide."
Coroner Shortland said the car would have filled "reasonably quickly and the two women had no chance of escaping given the circumstances of the tragedy".
"There would have been extreme panic," he said.
"They would have been familiar with their environment and the roads and this was simply an error of judgement.
"One cannot underestimate the impact of the high alcohol reading, irrespective of who was driving the car."
Coroner Shortland concluded that both women died of drowning.
"This would have been a horrific death for both women in the circumstances. It is yet another reminder of the dangers of drinking and driving."
Ms Solomon-Tauhinu and Ms Fisher were socialising with friends and family in the evening and early morning before their crash.
They left the home of a friend on Creamery Rd in Ms Solomon-Tauhinu's car and were driving along Hawkins Rd when their vehicle lost control at a T-intersection.
The car went over the edge of the road and landed on its roof in a "deep, tidal mangrove" swamp.
Coroner Shortland said the tide was at its highest at that time and would have "totally submerged the vehicle".
The crashed car was not found until more than six hours later when local man, Harding Morunga, spotted it as he drove past.
Mr Morunga could not open the doors because they were partially submerged in mud and he needed to use a hammer to break through the left rear passenger side window to reach the women inside.
An investigation of the crash scene found there was very little seal edge on the side of the road closest to the sea, indicating "no room for driver error".
Coroner Shortland said Ms Solomon-Tauhinu was most likely the driver because of her position in the car but he said that could not be found conclusively.
