Waves up four meters high cut through jetties and swallowed homes in a coastal village in the south-central province of Phu Yen on Sunday night.
Families from Ro village in Tuy Hoa town stayed up most of the night, fearful of their lives, while the sea ravaged roughly one kilometer of a jetty built last year.
Truong Thi Tiem, a villager, said the high tides took everyone aback as there was no storm or strong winds.
Tiem said the tide started rising at around 6pm and the waves continued to build until 4am on Monday.
“Waves nearly four meters high just fell on my house. Water flew into the house and collapsed the back wall,” she said.
She said no one was prepared to evacuate and they only had time to carry off children and old people, she said.
“I had to just leave my assets there. Nearly a third of the house was flooded… Lucky there was little wind last night, or the entire area would have been gone.”
At least 40 houses were damaged.
Truong Tan Hung’s house was flattened into a pile of debris.
His furniture now sits buried under broken bricks and corrugated tin.
“I just had time to get my wife and children away and bring some clothes,” Hung said.
He said he lost more than VND200 million (US$9,425) in the loss of his 70-square-meter house. Vietnam's per capita income was around $1,900 last year, according to the World Bank.
“Now we don’t know how we'll live,” he said.
Tides also collapsed a 10 meter wall at a seafood processing plant, killing more than VND40 million ($1,885) worth of breeding shrimp.
Nguyen Moc, a long-time resident and fisherman, said high tides have been swallowing houses in the area for years.
The sea has eaten around 300 meters into the land since 2003.
Moc said the destructive tides usually come late at night and last early into the next morning, giving people no time to gather their possessions.
His neighbor, Nguyen Thi Nguyet, said Sunday's high tides were the worst.
“I have never seen anything that surprising and terrible. My husband and I had just brought our two children outside when our house collapsed,” Nguyet told news website VnExpress.
Locals said the high tides usually last for days at a time.
Those who lost their homes say they have nowhere to sleep in the nights to come.
Tiem said the government should relocate the entire village to some place safer.
The Phu Yen Province government has ordered Tuy Hoa officials to build a relocation shelter for the nearly 180 vulnerable families, but they cited a lack of funds for indefinite delays.