The campaign, with 16 presidential candidates including leftist Luisa Gonzalez and Indigenous leader Leonidas Iza, will end February 6, three days before the election.
The National Electoral Council (NEC) called on all candidates to conduct campaigns of "tolerance and mutual respect that promote reasoned debate (and) a culture of peace."
Despite drug-related violence and a serious drought that led to prolonged blackouts, Noboa leads in early opinion polling, at 33 percent.
Gonzalez, a 47-year-old lawyer close to opposition leader and former president Rafael Correa, is not far behind, at 29 percent, according to a recent survey by the Comunicaliza firm.
"A united, brave and hopeful country is about to be reborn," Gonzalez said on X before launching her campaign in capital Quito and the port city of Guayaquil, a city so hard-hit by drug-related crime that Noboa last year deployed army troops there.
Iza, who heads the country's largest Indigenous organization -- and who took part in uprisings that overthrew three presidents between 1997 and 2005 -- placed a distant third in the polling at 3 percent.
Political spat
The pro-Noboa ADN political alliance is planning a caravan in Guayaquil, though it was unclear whether the president -- locked in a spat with Vice President Veronica Abad -- would take part.
The government accused her of being slow to take up a temporary foreign posting -- which she said was designed to pressure her to resign.
In response, Noboa has designated Cynthia Gellibert as interim vice president.
If Noboa requests the traditional leave of absence to campaign ahead of the election, the vice president would normally fill in.
Abad has challenged the Gellibert appointment, saying on X: "I will assume the presidency... while President Daniel Noboa participates as a presidential candidate."
The government, however, contends that Noboa is not required to take a leave of absence.
