Mayor Alfredo Lim ran for the mayorship for the third consecutive time; if he won, he would have been prohibited to run in 2016 due to term limits.

Lim's opponent was former senator, vice president, deposed president then convicted plunderer and defeated 2010 presidential candidate, Joseph Estrada, who was a longtime San Juan mayor; in order to run for the mayorship, Estrada had to transfer his residence from San Juan to Manila.

Estrada's running mate was Vice Mayor Isko Moreno, who has served since 2007; had he won, he would be term-limited in 2016.

On May 4, 2012, Vice Mayor Isko Moreno joined the Pwersa ng Masang Pilipino party, fueling speculations that he would be former President Joseph Estrada's running mate.

[4] On September 18, 2012, Lim announced that he has picked 6th District Councilor Lou Veloso to be his running mate.

Estrada left his home at Santa Mesa with Moreno aboard his jeepney he made famous during the 1998 presidential election.

[4][11] Aside from Lim and Estrada, other candidates include Marino Magallanes, a fortune teller from Quiapo, mechanical engineer and perennial candidate Onofre Abad, lawyer Felix Cantal, Samuel Gabot, Rodolfo Lim and driver Fidel Cruz.

On January 7, 2013, the Sandiganbayan ruled to dismiss via technicality a petition disqualifying Estrada from running due to a condition from his pardon granted by President Gloria Macapagal Arroyo that said he would not seek elective office.

"[14] The two camps signed a covenant for peaceful elections at the Manila Police District headquarters on February 15, 2013.

[15] A day later, the police arrested Moreno and five other UNA candidates for the city council for alleged illegal gambling.

Moreno and the other candidates were freed after the Manila Prosecutor's Office ruled that there was not enough evidence to prolong their detention.

Judge Marivic Umali heeded Estrada's lawyer Frank Chavez that the Commission on Elections and not the court had jurisdiction on the case.

6 Arlene Chua's term was cut short because of citizenship issues and was declared ineligible for office by COMELEC.