Since December 2022, she serves as Ambassador and Permanent Representative of Thailand to the United Nations Offices in Vienna.

Mangklatanakul has engaged in negotiations and conferences including the United Nations Commission on International Trade Law (UNCITRAL), Association of Southeast Asian Nations (ASEAN), Indian Ocean Rim Association (IORA), Ayeyawady-Chao Phraya-Mekong Economic Cooperation Strategy (ACMECS) and other multilateral fora.

[5] She was chief negotiator for Bilateral Investment Agreements (BITs) and Free Trade Agreements (FTAs), advocating for investor-state dispute settlement (ISDS) reform, while maintaining an interest in alternative dispute settlement as well as international trade law and its impact from climate change.

In September 2023, Mangklatanakul was elected as the President of the 67th Regular Session of the General Conference of the International Atomic Energy Agency (IAEA).

Mangklatanakul has also served on the Thailand Arbitration Center Board of Directors, the Malaysia-Thailand Joint Authority Board, the Anti-Money Laundering Office and most recently the Parliamentary Committee on the Impact of Thailand Accession to the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP).