At Straatman Koster advocaten, Thomas is primarily engaged in construction and procurement law. In particular, his work consists of drafting and assessing agreements, advising on construction law issues and conducting proceedings in both the civil courts and the Council of Arbitration. Thomas also advises and litigates on procurement law issues such as the preparation of the procurement procedure, the evaluation of tenders and the award decision.

Thomas graduated in 2022 from Erasmus University where he took the master's degree in Private Law. At the Vrije Universiteit Amsterdam, Thomas obtained his master's degree in Construction Law (cum laude). His thesis on the right to extension of time under the UAV 2012 in case of 'improper concurrence' of causes of delay was awarded the thesis prize by the Institute for Construction Law in 2023. Thomas has been an attorney at Straatman Koster advocaten since December 2024.