Raul Castro from Cuba and Salvador Sanchez from of El Salvador arrived on Sunday to witness the historic signing.
“It has to be a stable peace, a lasting peace, we can not build development without peace,” said president Sanchez. “A new history opens up for Latin America.”
The presidents of Costa Rica and Peru have also arrived, and the rest of the leaders are expected to fly to Cartagena Monday.
The heads of state of Argentina, Bolivia, Chile, the Dominican Republic, Ecuador, Guatemala, Honduras, Mexico, Panama, Paraguay, and Venezuela have all confirmed their attendance.
The deal, which will bring an end to over five decades of armed conflict, is widely considered to be one of the most significant events in the history of Colombia, with repercussions for the rest of the region.
A number of former presidents, including Jose Mujica of Uruguay and Felipe Gonzalez of Spain, have also said they will attend.
U.N. Secretary General Ban Ki Moon, a supporter of the Colombian peace process, will also travel to Cartagena, alongside the High Commissioner for Human Rights Zeid Ra’ad al Hussein and Gerard van Bohemen, the head of the Security Council.
U.S. Secretary of State John Kerry along with the heads of the Organization of American States, World Bank, International Monetary Fund and the Inter-American Development Bank will also participate.
The representatives of the FARC-EP took off from a remote region of the country known as the Yari Plains on Saturday upon the conclusion of the 10th National Guerrilla Conference, where 200 delegates voted to unanimously approve the peace deal.
“We’re all pulling for peace. We’re going to get peace, for everyone. It’s a must. We’re going to the signing,” the FARC’s high commander Timoleon Jimenez, better known as Timochenko, said before he boarded a helicopter.
Approximately 2,500 people in total are expected to witness the signing of the deal with another thousand journalists also expected to cover the event.
The ceremony will be an all-day event with the actual signing occurring at 5 p.m. local time. The deal will be signed by President Juan Manuel Santos and the leader of the Revolutionary Armed Forces of Colombia, Timochenko.
The text of the pact will later be submitted to a popular vote in a plebiscite to be held next Oct. 2. Poll indicate the deal will be approved by a wide margin.