The Customs Surveillance Service ( SVA ) is an institution traditionally linked to the fight against tobacco smuggling. Thus, its historical origins are found in the bodies that, depending on or under the supervision of the Royal Treasury, had the aforementioned mission with various names, structures and organic affiliations: Safekeeping (maritime and land), Special Land and Maritime Surveillance Service of the Tobacco Leasing Company, Special Land and Maritime Surveillance Service of Tabacalera SA or Special Fiscal Surveillance Service. It received its current name in 1982 following the approval of Royal Decree 319/1982 of 12 February, which restructured and assigned the Customs Surveillance Service directly to the Ministry of Finance through the General Directorate of Customs and Special Taxes.

Currently, the SVA is integrated into the Tax Agency at the central level, through the Deputy Directorate of Customs Surveillance, which depends organically and functionally on the Customs and Excise Department.

In terms of organisation, the Deputy Directorate of Customs Surveillance is made up at the central level of the General Subdirectorate of Operations (responsible for the planning, execution and coordination of operational activity) and the General Subdirectorate of Logistics (responsible for technological management, supervision and control of the means used and other aspects related to the quality of the actions and procedures).

At the territorial level, the Regional Customs Surveillance Areas are organically integrated into the Special Delegations of the AEAT under the direction of the Head of the Regional Customs and Excise Department. It has Operational Investigation Units, Maritime Bases and Air Bases spread throughout the national territory.

The SVA is made up of approximately 2,200 officials of different categories (A1, A2 and C1) and specialties (Investigation, Navigation, Propulsion and Communications) and has aerial means (helicopters, drones and airplanes), naval (52 vessels, including two Special Operations Vessels for actions on the high seas in the repression of drug trafficking), land (610 vehicles), communications centers, technological means applied to investigation, non-intrusive inspection systems and radiological control, etc.

As a curiosity, the Maritime Service of the SVA has its own flag, the origin of which dates back to 1787, when Charles III authorized the use of the national flag by vessels of the Royal Treasury. The current flag of the SVA vessels, in accordance with Royal Decree 1511/1977, of January 21, approving the Regulations on Flags and Standards, Banners, Insignia and Distinctions, is the national flag with two blue H's crowned (with the Royal Crown) in blue on the yellow stripe. The regulation specifies that this flag will be used on ships or boats of (or in the service of) the Ministry of Finance.

The SVA carries out its functions basically in three main areas: investigation, aeronaval and customs premises, and constitutes, in short, a police service of the Ministry of Finance, with jurisdiction over smuggling and economic crime.

Its activities are aimed at repressing smuggling crimes and offences, combating drug trafficking and other related crimes such as money laundering, excise tax fraud and other tax frauds, and the underground economy. It also carries out important support work for other departments of the Tax Agency (mainly Inspection and Collection) in the fight against tax fraud and the black economy. For this reason, they have extensive training in administrative, criminal, procedural, community, tax, customs and anti-smuggling law.

The SVA has the status of Fiscal and Customs Guard, responsible for preventing and prosecuting smuggling, fraud and other fiscal crimes throughout the national territory.

Customs Surveillance officers, both men and women, are agents of authority (fiscal police and judicial police), and given the missions they perform, they are authorized to use regulation weapons. Furthermore, it is a partially uniformed service. In addition, in the exercise of their functions, they assist the judicial bodies or the Public Prosecutor's Office in those cases in which their action is required as officials of the Tax Agency who hold the status of Judicial Police.