noun
implementation date; date of execution
Refers to the scheduled date on which a plan, event, or measure is to be carried out. Common in official and business contexts.
新しい制度の実施日は来月の1日です。
The implementation date for the new system is the 1st of next month.
イベントの実施日が変更になりました。
The date of the event has been changed.
日程 is a broader term for 'schedule' or 'itinerary', whereas 実施日 pinpoints the exact date of execution.
Compound of 実施 (implementation) + 日 (day).