About 3.8 million Croats are eligible to cast votes on Sunday for one out of a total of eight candidates, three of whom are women, ranging from left to the right on the political spectrum.
Incumbent President Zoran Milanovic, the opposition Socialist Democrats' candidate, will run for a second term.
His main challenger is Dragan Primorac, a former science minister backed by the governing Croatian Democratic Union.
The election will go to a second round if none of the candidates wins a majority of the vote.
Milanovic has led in opinion polls before and after the election campaign, which analysts described as dull and uninspiring.
The latest poll published on Friday by Nova TV Daily News showed Milanovic leading with 37 per cent support against Primorac with 20 per cent support.
The next in line are two women - independent candidate Marija Selak Raspudic and Ivana Kekin of the We Can! (Mozemo) left-wing, green political party, who have garnered about 10 per cent support each in the poll.
The first preliminary results will be known about an hour after polls close on Sunday night and official results are expected in the following days.
The presidential role is to a large extent ceremonial as the head of state cannot veto laws, but has a say in foreign policy, defence and security matters.
During his term, Milanovic, a former prime minister and a populist, has confronted Prime Minister Andrej Plenkovic over foreign and public policies, with insults often traded between the two men.
