The elections in Thailand's 76 provinces outside the capital Bangkok are the first since Prime Minister Prayuth Chan-ocha, who kept power after last year's ballot, overthrew an elected government in a military coup.
"It's my duty to vote," said 27-year-old bank worker Korkiet Akaraparn, voting in his first provincial election in Nonthaburi, on the outskirts of Bangkok. "I hope that there will be new people from this election who bring change."
Polling officials reported a steady turnout despite Thailand's biggest daily surge in coronavirus cases on Saturday in a province outside Bangkok. Polls close at 5 p.m. (1000 GMT), with results expected from the evening.
Among the parties putting up candidates is the Progressive Movement, which has its roots in the now banned Future Forward Party of Thanathorn Juangroongruangkit.
Thanathorn had emerged as the most vocal challenger to Prayuth. When he and his party were banned from politics, it prompted protests demanding the removal of Prayuth, a new constitution and reforms to the powerful monarchy.
Prayuth rejects accusations that he engineered the general election to keep power.
Although the party backing him in parliament is not formally putting up candidates in the provincial elections, contestants in races across the country are making clear their loyalty to his camp.
The elections are also a test for the Pheu Thai Party linked to populist former prime minister Thaksin Shinawatra. In opposition it remains the largest party in Thailand's parliament.
Thaksin, who rarely comments in public from self-exile since being overthrown in 2006, has posted on Twitter to encourage people to support the party ahead of provincial elections, in which powerful families traditionally hold local sway.
"I voted for candidates who are relatives of the former chief," said Charoen Buaperm, 60.
Provincial administrations are responsible for the provision of local services and development plans and run their own budgets. The Progressive Movement seeks to devolve more power to provinces from Bangkok, which is not yet holding its own local election.