It's a blow for the tourism-dependent nation, which was looking to reopen and to celebrate its New Year holiday.
SCOTT HEIDLER: This is what streets across Thailand should look like this week. Here locals and tourists in Bangkok's backpacking hub of Khaosan Road out in mass, celebrating the Thai Songkran. New year with parties and water fights
But on Khaosan Road this year and nationwide, the party has been canceled. A recent spike in COVID cases is thought to have started at nightlife spots in Bangkok has raced across the country.
Thailand has been viewed as a COVID success story with low infection rates. But now, a third wave is here, throwing cold water on the hopes of many in the tourist and hospitality industry just as it was positioning for rebound.
Bee has run her hair braiding shop along Khaosan Road for so long she doesn't even remember when she started. As she relies on backpacking tourists, she might have to close for good.
BEE: Yeah. Yeah.
BEE THROUGH INTERPRETER: This is a very tiring time. After the first outbreak, I still had some savings left. After the second outbreak, things got a little bit better. But the latest wave is looking like the worst. I don't know what to do.
SCOTT HEIDLER: Despite the dim outlook, some are still setting up for Songkran but without the celebrations.
What's deeply concerning to health officials about this new wave is that some of the cases have the highly transmissible UK variant. And this week has seen the largest daily infection rates of the pandemic.
DR. CHALERM HARNPHANICH THROUGH INTERPRETER: New patients from this third wave are mainly from Bangkok's middle class with the capability to move around. Our concern is the quarantine and isolation of new patients. Hospitals are running out of space.
SCOTT HEIDLER: When the first clusters were discovered, the need for testing was so great many private hospitals ran out of COVID testing supplies.
Prime Minister Prayut Chan-o-cha announced that there would not be a national lockdown but each province could decide entry restrictions. His government directly hit by the new wave. At least five cabinet members are now in quarantine, including the Minister of Health.
Only about 500,000 doses of COVID vaccines have been given to the population of 69 million people. Some in the opposition see the lagging vaccination program as one of multiple failings by the administration.
VIROJ LAKKANA-ADISORN THROUGH INTERPRETER: They really underestimated the severity of the crisis and failed on sourcing more vaccine options. They did not continue with COVID readiness set at the beginning of the pandemic. They were not ready to immediately respond to this wave.
SCOTT HEIDLER: Wishing that next year Songkran will again look like it's supposed to, most Thais will be closely watching the infection rates over the next two weeks. Hoping there won't be a spike after everyone returns to work after the holiday. Raising the possibility of a happier new year.
Scott Heidler, Al Jazeera, Bangkok.