Some saw revenues plummet by 70 percent year-on-year, the city Department of Tourism said.
The first wave appeared in late January, just a few weeks before the Lunar New Year holidays.
It died down, and after over a month without new cases, the latest wave triggered by new virus strains began on April 27.
According to the department, around 5,000 travel firms remain in operation though some large ones have cut their payroll by 50-80 percent to reduce costs.
The hospitality industry has been devastated by the lack of tourists, with three- to five-star hotels reporting a 70 percent fall in revenues and some even temporarily closing down.
The city received 7.1 million domestic tourists in the first five months of this year, down 47 percent from 2019, and earned revenues of VND35.5 trillion ($1.54 billion), down 37 percent.
The southern metro has had 819 Covid infections in the latest wave, forcing authorities to close all tourist destinations and pedestrians-only streets since early June.