...Two of those hoping to beat Mr Mulino also are very well-known names in Panamanian politics.
Martín Torrijos was president from 2004 to 2009 and is the son of Omar Torrijos, the military ruler who signed a treaty with the US to restore the Panama Canal zone to Panamanian sovereignty in 1977.
The 60-year-old is campaigning under the slogan "Safe Change". He has promised investment in the Panama Canal, one of the main drivers of Panama's economy.
Martín Torrijos has been president before and his campaigning simply under his first name
He is standing for the People's Party, which he joined last year after leading the Revolutionary Democratic Party (PRD).
Rómulo Roux, 59, a former president of the Panama Canal's board of directors is running for the national presidency for the second time, after losing to current President Laurentino Cortizo in 2019.
The lawyer, who is standing for the Democratic Change party says that if he is elected, he will implement an "aggressive" job creation scheme and improve public services....