Ofilio J. Mayorga

International Associate - Washington, D.C.

Ofilio Mayorga

Contact Information



omayorga@foleyhoag.com Download vCard

Ofilio Mayorga is an international associate in the firm’s International Litigation and Arbitration practice in Washington D.C. His practice focuses on public international law litigation, investment treaty arbitration and international commercial arbitration.

He has represented sovereign States, State-owned entities and private companies before the world’s principal dispute resolution bodies, including the International Court of Justice (ICJ), the Permanent Court of Arbitration (PCA) and the International Center for the Settlement of Investment Disputes (ICSID). He has also represented clients in numerous investment and commercial arbitrations conducted under the ICSID, UNCITRAL, and ICC Rules, in disputes involving natural resources, telecommunications, construction, shipping, civil aviation and joint ventures. Among other high-profile disputes, he successfully acted as Counsel for the Oriental Republic of Uruguay in Italba Corporation v. Oriental Republic of Uruguay, ICSID (Case No. ARB/16/9) and the Republic of India in Louis Dreyfus Armateurs SAS v. The Republic of India (PCA Case No. 2014-26), in which Foley Hoag obtained full dismissal of the claims and costs awards. The list of clients he represents includes Nicaragua, Qatar, Uruguay, Peru, Panama, Ecuador and India. 

Mr. Mayorga publishes and speaks regularly on issues of public international law and international dispute settlement. He has taught public international law at Tufts University and the law of armed conflict at the Harvard Humanitarian Initiative (HHI). In 2008, he interned at the United Nations’ Office of Legal Affairs (OLA). 
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  • University of Michigan Law School, LL.M, 2010
  • Tufts University The Fletcher School of Law and Diplomacy, M.A.L.D., 2009
  • Universidad Americana School of Law (Nicaragua), LL.B, magna cum laude, 2006



Representative Experience

Litigation Before the International Court of Justice

  • Appeal Relating to the Jurisdiction of the ICAO Council under Article 84 of the Convention on International Civil Aviation (Bahrain, Egypt, Saudi Arabia and United Arab Emirates v. Qatar) & Appeal Relating to the Jurisdiction of the ICAO Council under Article II, Section 2, of the 1944 International Air Services Transit Agreement (Bahrain, Egypt and United Arab Emirates v. Qatar). Represents the State of Qatar in proceedings before the International Court of Justice constituting appeals against decisions as to the jurisdiction and competence of the ICAO Council.
  • Application of the International Convention on the Elimination of All Forms of Racial Discrimination (Qatar v. UAE). Represents the State of Qatar in this proceeding before the International Court of Justice arising from breaches of the ICERD by the UAE.
  • Case Concerning Construction of a Road in Costa Rica along the San Juan River (Nicaragua v. Costa Rica). Represented Nicaragua in a dispute against Costa Rica before the ICJ regarding environmental and other damage suffered by Nicaragua as a result of Costa Rica’s construction of a road along the southern bank of the San Juan River and other irresponsible land use. 
  • Case Concerning Certain Activities Carried Out by Nicaragua in the Border Area (Costa Rica v. Nicaragua). Represented Nicaragua in a dispute bought before the ICJ by Costa Rica regarding issues of territorial sovereignty and alleged breaches of environmental law in relation to Nicaragua’s environmental permitting and execution of a project to dredge the lower stretches of the San Juan River to ensure its navigability by small vessels.

Investor-State Treaty Arbitration Cases

  • Basilio Amorrortu v. Republic of Peru. Representation of the Republic of Peru in an UNCITRAL arbitration initiated by a former Peruvian citizen and current US national for alleged violations of the Trade Promotion Agreement between Peru and the United States for alleged irregularities in the bidding process in connection with the operation of oil blocks off the Peruvian coast.
  • Louis Dreyfus Armateurs SAS v. Republic of India. Represents India in a UNCITRAL Arbitration under the France-India bilateral investment treaty arising from a contract concerning the supply and operation of cargo handling equipment.
  • Italba Corporation v. Oriental Republic of Uruguay. Counsel to Uruguay in an ICSID arbitration under the US - Uruguay bilateral investment treaty concerning the regulation of claimant’s telecommunications permit.
  • MAESSA (Consorcio GLP) – Mantenimientos, Ayuda a la Explotación y Servicios S.A. Sociedad Española de Montajes Industriales S.A. v. Republic of Ecuador. Represents the Republic of Ecuador in an arbitration under the UNCITRAL rules.
  • Sacyr S.A. v. The Republic of Panama. Represents the Republic of Panama in a treaty arbitration initiated by Sacyr S.A., a Spanish entity, under the arbitration rules of the United Nations Commission on International Trade Law (UNCITRAL), relating to the Panama Canal expansion.
  • Rusoro Mining Limited v. The Bolivarian Republic of Venezuela. Represented Venezuela in a US$3.03 Billion claim brought by a Canadian gold mining company in an ICSID Additional Facility arbitration concerning the nationalization of the company's assets.
  • Merck Sharp & Dohme (I.A.) v. The Republic of Ecuador. Represents the Republic of Ecuador in an UNCITRAL arbitration under the Ecuador - U.S. bilateral investment treaty arising from the alleged treatment of a foreign investor by the Ecuadorean judiciary.
  • Murphy Exploration & Production Company-International v. The Republic of Ecuador. Represents the Republic of Ecuador in an UNCITRAL arbitration under the Ecuador – U.S. bilateral investment treaty arising from changes in domestic legislation pertaining to the exploitation of oil resources in Ecuador.
  • Valores Mundiales, S.L. and Consorcio Andino, S.L. v. Bolivarian Republic of Venezuela, ICSID Case No. ARB/13/11. Representing Venezuela in an ICSID arbitration concerning regulations in the food production sector.

International Commercial Arbitration

  • Metro de Lima Línea 2 S.A. v. Republic of Peru (ICSID Case No. ARB/17/3). Defending Peru in an ICSID arbitration arising out of a concession contract for the construction of line 2 of Metro de Lima.
  • Represents a Central American State in ad hoc construction arbitration under UNCITRAL Rules related to the construction of a 40km highway. 
  • Represents a Nicaraguan company in  ICC arbitration proceedings against a Colombian company related to corporate matters in the energy sector.
  • Represents a Nicaraguan agricultural company in ICC arbitration proceedings against Nicaraguan, Panamanian and Colombian companies related to the mismanagement of cane sugar plantations.

International Advisory Matters

  • Advised a Latin American nation on the renegotiation of its bilateral investment treaties.
  • Advised an International Humanitarian Organization on the protection of hospitals in armed conflicts.

Professional Experience

  • Guest Lecturer, Harvard Humanitarian Initiative (2012- 2016) 
  • Interned in the United Nations Office of Legal Affairs (2008)
  • Teaching Fellow in International Law, Tufts University Political Science Department (2008-2009)
  • Lecturer in International Arbitration, Universidad Americana (2010-2011)
  • "Arbitrating War: Military Necessity as a Defense to the Breach of Investment Treaty Obligations," Harvard Program on Humanitarian Policy and Conflict Research, Policy Brief, August 2013
  • “Occupants Beware of BITs: Applicability of Investment Treaties to Occupied Territories,” Palestine Yearbook of International Law, Volume 19 (2016), Issue 1, pp 136 – 176


  • 2021 Law360 Rising Star (International Arbitration category) 
  • Merit Award in International Commercial Arbitration, University of Michigan Law School, Ann Arbor, Spring Semester, 2010
  • Grotius Scholar, University of Michigan Law School, Ann Arbor, 2009-2010
  • The Fletcher School Board of Overseers Scholar, Tufts University, 2007-2009
  • Becario Líder, Fundación Carolina and Banco Santander Fellowship, Spain-Portugal 2006


  • Arbitrator, Nicaraguan Mediation & Arbitration Center
  • American Society of International Law
  • Moderator, “Environmental Protection before International Courts and Tribunals: Challenges and Opportunities”, 2019 International Law Weekend, New York City, October 11, 2019.
  • Panelist, “Arbitrabilidad de la contratación pública y en el derecho societario: Desafíos y panorama,” ICC Young Arbitrators Forum (YAF), Tegucigalpa, Honduras, September 26, 2019.
  • Panelist, “Arbitraje Comercial y de Inversión,” XIII Congreso Internacional de Arbitraje, Lima, Perú, September 11-13, 2019. 
  • Panelist, “Wars without Prisoners: Denying Quarter in the Age of Drone Warfare,” American Society of International Law Research Forum, Midyear Meeting, Los Angeles, California, November 8-10, 2018. 
  • Panelist, Colloquium on "International Investment Law & the Law of Armed Conflict" (Arbitration of Disputes under State Contracts in Times of Belligerent Occupation), Athens, Greece, October 2017 
  • Panelist, “Analysis of a Construction Arbitration Dispute: Challenges derived from Corruption Allegations,” ICC Young Arbitrators Forum (YAF), Bogotá, Colombia, March 8, 2017
  • Guest Speaker, “International Law and the War in Syria,” The Fletcher School of Law and Diplomacy (Medford, MA) November 2016
  • Panelist, International Law of the Everyday: Fieldwork, Friction, and Fairness, 24th Annual Conference of the Australian and New Zealand Society of International Law (ANZSIL), Australian National University College of Law, Canberra, Australia, 30 June - 2 July, 2016 
  • Panelist, The Legality of Foreign Investments under Bilateral Investment Treaties, IV Central American Arbitration Centers Convention, Managua, Nicaragua, 27-28 November, 2014
  • Guest speaker, The ICJ's decision in the Nicaragua v. Colombia maritime delimitation dispute, Universidad del Azuay, Ecuador, 2012
  • Guest speaker, Legal aspects of conflict over San Juan river of Nicaragua, Universidad del Azuay, Ecuador, 2010
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Bar Admissions

  • Admitted only in New York; not engaged in the practice of law in the District of Columbia
  • Nicaragua