Polls, however, show that an upstart leftist candidate, 36-year-old Jose Maria Villalta, could bring the left to power for the first time ever in this conservative, largely Roman Catholic country.
Villalta, a legislator and environmental activist, is a candidate for the leftist Broad Front (FA).
"We have a great opportunity today," he told reporters early Sunday as he took a jog around his neighborhood and bought bread for his family's breakfast.
Rodrigo Arangua, AFP
Costa Rican presidential candidate for the leftist Frente Amplio party Jose Maria Villalta (L) jogs before voting in San Jose during the presidencial election, on February 2, 2014
"We can have a surprise. Let's go for change," he said.
Rivals accuse Villalta, who is attracting the protest vote, of being a communist and of supporting abortion and gay marriage.
And local media reported death threats three days ago against the young candidate, citing judicial sources, who added that his security entourage had been reinforced.
An unpredictable outcome
Polls show almost equal support for two other candidates -- historian Luis Guillermo Solis, 55, with the centrist Citizen Action Party (PAC), and businessman Otto Guevara, 53, with the conservative Libertarian Movement (ML).
They also indicate that 30 percent of voters are undecided, and that none of the candidates have more than 40 percent of support, making an April 6 runoff likely.
And yet "it's not possible to assert anything with certainty," sociologist Manuel Rojas told AFP.
"There is a 75 percent possibility of a runoff vote, but there is still a margin for Araya to narrowly make it" to the 50 percent threshold, he said.
Ezequiel Becerra, AFP
A Costa Rican votes in the national election at a polling station in San Jose, on February 2, 2014
Araya is being held down by his association with Chinchilla, who has led the least popular government in the past 20 years.
"I came to vote with the hope that there is change," said housewife Iris Rodriguez, 45, who called on the next government to "think a little about the poor."
Leftist Villalta, a lawyer, has campaigned on a platform of fighting corruption and social equality in development, successfully positioning himself as the anti-Chinchilla candidate.
But as the campaign wound down, the political polarization gave a boost to Solis as a centrist option -- making the results difficult to predict.
"Whoever wins will head a weak government," Rojas said. "They will have to gain political legitimacy through their actions. They will not be able to govern only with their party, as has been past practice."
Voting began at 6 am (1200 GMT) and is scheduled to end at 6 pm (0000 GMT Monday). Election officials say they expect to have the first official results two hours later.