Called to the Bar of England and Wales in 1965, Mr. Kaplan has practiced as a barrister, Principal Crown Counsel at the Hong Kong Attorney General’s Chambers, and served as a Judge of the Supreme Court of Hong Kong in charge of the Construction and Arbitration List. 

From 1991 to 2004, he was Chairman of the HKIAC, and in 1999 – 2000, he was President of the Chartered Institute of Arbitrators. Since 1995, he has been a Council Member and now Governing Board Member of the International Council of Commercial Arbitration, and in 2012 he became a Member of the ICC International Court of Arbitration. He is a Chartered Arbitrator and a Fellow of the Chartered Institute of Arbitrators, the Hong Kong Institute of Arbitrators, and the Singapore Institute of Arbitrators. He is a panelist of several other arbitral institutions including CIETAC. 

Since 2017, Mr Kaplan has been the president of the Court of the Mauritius Chamber of Commerce and Industry Arbitration and Mediation Centre. In 2020, he was appointed first president of Delos Dispute Resolution's board of advisers. 

In addition to conducting arbitrations in England and Hong Kong, Mr. Kaplan has conducted arbitrations in the USA, France, Germany, Croatia, The Netherlands, Malaysia, Australia, Denmark, Sweden, Indonesia, South Africa, Norway, Philippines, China, Lao, Canada, Singapore, Korea and Japan. 

British