PRESS RELEASE Denison Reports CNSC Hearing Dates for Phoenix ISR Project Toronto, ON - February 27, 2025. Denison Mines Corp. ("Denison" or the "Company") (TSX: DML, NYSE American: DNN) is pleased to announce that the Canadian Nuclear Safety Commission ("CNSC") Registrar has set the schedule for the CNSC public hearing ("Hearing") for the Wheeler River Uranium Project ("Wheeler River", or the "Project"). The Hearing is scheduled to be held in two parts (October 8, 2025, and December 8 to 12, 2025) and represents the final step in the federal approval process for the Project's Environmental Assessment ("EA") and License to Prepare and Construct a Uranium Mine and Mill ("License"). Based on this schedule, if the CNSC makes a prompt decision to approve the Project following the completion of the Hearing, the Company expects to be able to commence site preparation and construction activities for the Phoenix In Situ Recovery ("ISR") project in early 2026. Continue reading this press release by visiting Denison's website at www.denisonmines.com.