Tosca van Halsema specializes in project development, environmental and environmental law, and general administrative law. She advises and litigates for project developers, construction companies, investors and governments. She also regularly assists developers and governments in negotiating area and project developments and writes or reviews related contracts.

Tosca graduated cum laude in 2013 with a degree in Constitutional and Administrative Law and European Law from Maastricht University. After graduating, she started working as a lawyer at Loyens & Loeff in Rotterdam in the Competition & Government practice group. Tosca has been working at Straatman Koster advocaten since September 2019, where she was appointed partner in 2026.