Daniel So, a 65-year-old who works in technology, was among the first queuing at a polling centre in the wealthy Mid-Levels district.
"The young people are not so interested in this election because they are misled by foreign politicians and media," he told AFP. "China is doing so great now."
As Hong Kong leader Carrie Lam arrived to cast her vote, three protesters from the pro-democracy League of Social Democrats party chanted: "I want genuine universal suffrage".
"(Lam) said this was an improvement of the electoral system, but in reality, it stripped Hong Kongers of their right to vote," activist Chan Po-ying told reporters.
The government bought up newspaper front pages and billboards, sent flyers to every household, pinged mobile phones with reminders to vote and made public transport free for the day.
Despite the publicity blitz, the latest polls showed only 48 per cent of respondents said they would vote – a record low – and 52 per cent said they found no candidate worthy of support.
Starry Lee, chair of the biggest pro-Beijing party, the DAB, urged people to participate.
"The polling stations' feedback showed that not many people are voting," she told reporters.
An accountant in her 20s, who gave her name as Loy, said she had no plans to use her ballot.
"My vote won't mean anything because ultimately it's Beijing's people winning," she told AFP.
In North Point, a district known for pro-government support, a 74-year-old man who gave his surname Lo said he did not know most of the "new faces" on the candidate list but still voted.
"I picked those who would voice opposition, not the yes-men," he told AFP.
Lam has sought to manage expectations, telling state media last week that a low turnout could indicate "the government is doing well and its credibility is high".
Independent polling places her public approval rating at around 36 per cent.
Sunday's election has received vocal backing from Beijing, which sees the new system as a way to root out "anti-China" elements and restore order in a legislature freed from a disruptive opposition.
Critics counter that China has all but banned opposition politics in a city that once boasted a rambunctious political scene.
Dozens of prominent opposition figures – including many democrats who won legislature seats in the previous election – have been jailed, disqualified or have fled overseas.
The city's biggest pro-democracy parties have put forward no candidates and a growing number of Hong Kong activists abroad have also openly advocated a boycott.
"People do not want to vote for a rubber-stamp chamber and pretend everything is all right," Nathan Law, a former lawmaker now living in Britain who is wanted by Hong Kong authorities, tweeted on Sunday.
"This is a fake election and the worst regression in our electoral system," added Brian Leung, an activist now based in the United States.
Hong Kongers are allowed to cast blank ballots or not vote.
But earlier this year, authorities made it a crime to "incite" others to boycott elections or cast blank or spoiled ballots.
Authorities have arrested 10 people under this law so far, mostly for social media posts.
They have also issued arrest warrants for activists overseas who have called for a boycott and threatened Western media outlets with prosecution for editorials critical of the new political system.
Police said they would deploy more than 10,000 officers across the city.