In 1997, Oñate Laborde became Ambassador of Mexico to the United Kingdom, position he would hold until 2001, year when he became Ambassador of Mexico to the Netherlands. While serving as ambassador in the Netherlands, he also acted as the Permanent Representative of Mexico to the Organisation for the Prohibition of Chemical Weapons. His term as ambassador ended in 2003, but he would continue his activities in the OPCW, serving as legal adviser and later on as special adviser to the Director General. In 2013 he became the Permanent Observer of Mexico to the Council of Europe, in Strasbourg, France.
Laborde, Santiago Oñate (1978), El acceso a la justicia y los no privilegiados en México (Access to justice and the underprivileged in Mexico) (in Spanish), Revista de Derecho Procesal. Iberoamericana
Woolomes Tabassi, Lisa; Laborde, Santiago Oñate; Rugarabamu, Donata (2010), OPCW: The Legal Texts (2 ed.), Asser Press, ISBN978-90-6704-318-2
"La Acción Procesal en la doctrina y en el derecho positivo mexicano", Mexico, 1972.
"El Estado y el Derecho", S. Oñate and D. Pantoja, Anuies-Edicol, Mexico, 1977.
"Evolución del Derecho Procesal Mexicano", in LXXV Años de Evolución Jurídica en el Mundo, UNAM, Instituto de Investigaciones Jurídicas, Mexico, 1978.
"Legal Aid in Mexico", in F. Zemans Legal Aid, Pinter Publishers, London, 1979.
"Legal Needs of the Poor and Disadvantaged", B. Garth, ed., Madison, Wisconsin, 1983.
"Los trabajadores migratorios frente a la justicia norteamericana", S.T.P.S.-FONEP, Mexico, 1983.
"El papel de juez en la resolución de Litigios Familiares", in International Congress of Comparative Law; National reports, H. Nakamura (ed.) Tokio, Japan, 1984.
"Administración de justicia y composición de conflictos laborales", in El Obrero Mexicano, Vol. 4, 21st century, Mexico, 1985.
"El Veto Suspensivo", in El Refrendo y las Relaciones entre el Congreso y el Ejecutivo, UNAM-Porrúa, 1987.
"El regimen de partidos", in Jornadas Jurídicas Nacionales, Fenase-Porrúa, 1987.
"Fuentes e interpretación del derecho parlamentario", in Derecho Parlamentario Iberoamericano, Porrúa, 1987.
"Nuevos mecanismos de defensa del ciudadano frente a la administración pública", in Administración Pública Contemporánea en México, Mexico, 1993.
"Presidentialisme en democratie. Het geval van Mexico", in Drie Kwesties in Latijns Amerikas, L. Malaver and M. Oostra., ed. LASO, Amsterdam, 2002.
"Decision on the Follow-up to the OPCW Action Plan on Article VII: Ensuring the Effective Implementation of the Chemical Weapons Convention", with L. Tabassi and Ralf Trapp, The CBW Conventions Bulletin, 69–70, September–December 2005, pp. 5–10.
"Lessons learned: Chemicals trader convicted of war crimes", with B. Exterkate, L. Tabassi and E. van der Borght, Journal Judiciaire de La Haye, volume 2, number 1, 2007, pp. 23–42.
"Sustaining follow-up to the Action Plan on Article VII: National Implementation of the Chemical Weapons Convention", with M. Lak, L. Tabassi and K-S. Melzer, in Chemical Disarmament, volume 5, number 1, March 2007, pp. 18–24.
"Industry Role in the Non-proliferation of Chemical Weapons", International Law Association, 74th Conference, The Hague, August 2010.
"The Chemical Weapons Convention: An Overview", Audiovisual Library of International Law, UN, 2010.
"The Relation between Due Process in International and National Human Rights Instruments and International Adjudication Mechanisms", en The Development and Effectiveness of International Administrative Law, edited by O. Elias, Martinus Nijhoff, Leiden-Boston, 2012, pp. 375–385.