 The Central America-4 Border Control Agreement (CA-4) was a treaty signed in June 2006 between the Central American nations of El Salvador, Guatemala, Honduras and Nicaragua, establishing the free movement across borders between the four signatory states of their citizens without any restrictions or checks.Foreign nationals who enter one of the signatory countries can also travel to other signatory states without having to obtain additional permits or to undergo checks at border checkpoints.As of 1 January 2017, Salvadoran citizens had visa-free or visa on arrival access to 120 countries and territories, ranking the Salvadoran passport 39th in terms of travel freedom according to the Henley visa restrictions index.