Close behind the front-runner is Jussi Halaaho of the far-right Finland Party, who experts believe could also advance to the second round.
Voting will open at 9am (7am GMT) and close at 8pm.
Relations between Moscow and Helsinki soured following Russia’s invasion of Ukraine in 2022, and Finland ended its decades-long military non-alignment relationship and joined NATO in April 2023.
Russia, which shares a 1,340-kilometre (830-mile) border with Finland, immediately warned of “countermeasures.”
In August 2023, Finland observed an influx of migrants entering the country through its eastern border without visas.
Helsinki claimed Moscow was pushing hybrid attacks on migrants to destabilize and Finland closed its eastern border in November.
“We are now in a situation where Russia, especially Vladimir Putin, is using humans as weapons,” Stubb said in the final televised debate Thursday night.
“This is an immigration issue and a callous and cynical measure. In that case, we must put Finland’s safety first,” he added.
Main rival Haavisto stressed that Finland needed to “send a clear message to Russia that this cannot continue”.
After the Cold War, Helsinki maintained good relations with Moscow.
Incumbent President Sauli Niinistö, who is retiring after two six-year terms, was proud of his close relationship with Russian President Vladimir Putin, but has since become one of Putin’s harshest critics. became.
Against this backdrop, all presidential candidates are defending both Finland’s independence and its new role as a member of NATO, said Hanna Wass, deputy dean of the Faculty of Social Sciences at the University of Helsinki.
“They all seem to have strong ideas that emphasize self-sufficiency. In the future Finland should be independently responsible for its defense and actively contribute to the building of a shared European defense and Nordic cooperation. ” Wass said.
Tuomas Forsberg, a foreign policy professor at Tampere University, said a similar stance would lead to more emphasis on candidate character in elections.
“This will be less about choosing an individual and more about that person’s credibility and trustworthiness and their perceived qualities as a foreign policy leader,” Forsberg said.
According to a public opinion poll released by public broadcaster Yell, in the first round of voting, Stubb came in first with 27% of the votes, followed by Hervist in second place with 23% and Haraho with 18%.
Stubbe served as Prime Minister of Finland from 2014 to 2015, and Pekka Haavisto held several cabinet positions.
“Both men have extensive experience in both domestic and international politics, which voters seem to value most,” Wass said.
Forsberg pointed out that while Haavist and Stubbe share similar political views, they represent different backgrounds.
“Their backgrounds and values are seen as completely different, because Alex is more representative of the right and Harvist is more representative of the left,” he said.
“Even if Haavist tries to emphasize that there is nothing red about him and that he has chosen the middle path as a green man,” Forsberg added.
Forsberg said a second round of voting between the two candidates, which will take place on February 11 unless a candidate receives more than 50% of the votes, could prove decisive in the election debate.