The two frontrunners are Claudia Sheinbaum of the ruling Morena party, supported by the governing coalition Let’s Keep Making History (Sigamos Haciendo Historia), and Xochitl Galvez, supported by a coalition of opposition parties.

Jorge Alvarez Maynez, a third candidate, is running on behalf of the Citizens’ Movement.

As the first few votes started trickling in, Sheinbaum grabbed an early lead, followed by Galvez, in keeping with opinion polls that placed the Morena candidate as the firm favourite to win the presidency.

In addition to the presidency, voters also cast their ballots for about 20,000 positions in what is the country’s largest-ever election.

According to Mexico’s National Electoral Institute (INE), these positions include 128 Senate seats, 500 deputy seats, the governorship of Mexico City, and governorships in eight states including Chiapas, Guanajuato, Jalisco, Morelos, Puebla, Tabasco, Veracruz and the Yucatan.

Here is how the three parties are performing in the presidential vote, according to the latest updates from the INE:

When will we know the final results?

The results will likely be finalised only by June 8.

However, on June 2, Mexicans will have access to the quick count, a statistical projection estimating voting trends from a random sample of 7,500 polling stations.

Between 10pm and 11pm (starting at 03:00-04:00 GMT) on June 2, the INE will announce the quick count results of the presidential election. This announcement will be delivered in a televised message broadcast nationwide.

Starting at 8pm (02:00 GMT) on Sunday, the INE will also launch the Preliminary Electoral Results Program (PREP), a system that gathers and publishes data recorded by polling station officials. Al Jazeera will be relying on this data for its vote count tracker, while also sharing the quick count when it is announced by election officials.

When will the new president take charge of Mexico?

Mexico’s newly-elected president will be inaugurated on October 1, 2024, four months after election day.

This marks the first time the inauguration will occur on October 1 instead of December 1, following a change in the electoral law in 2014.

Besides the presidency, what other races are closely watched?

Other than who will be the next leader of the country, the race for Congress remains key.

The ruling party Morena aims to achieve a two-thirds majority in Congress, important for revising the constitution and eliminating what it perceives as cumbersome and wasteful oversight agencies. The opposition, united in a loose coalition, says this action would pose a threat to Mexico’s democratic institutions.

This could also affect the peso and how investors react to the election.

“If [Morena] wins two-thirds of the Congress, or gets eerily close, that becomes a tougher decision for investors because that becomes a very different scenario, in which there’s less constraints to power,” Miguel Angel Toro Rios, the dean of the School of Social Sciences and Government at Tecnologico de Monterrey, told Al Jazeera.

In Mexico City, the competition is fierce, with Clara Brugada of the ruling party, Santiago Taboada of the largest opposition coalition and Salomon Chertorivski of the Citizens’ Movement all locked in a tight race.

Governorships in large, populous states such as Veracruz and Jalisco are also drawing interest.