The Semi-Marathon d'Alcácer is a 21.097 km road race held in Alcàsser, Valencia. Organized by Club de Atletismo Alcácer, the race begins at the municipal sports center and concludes in Plaza del Castillo. It features a homologated half marathon distance with chip timing.
The route crosses Alcàsser’s primary local landmarks before concluding in the town square near the castle. A 10 km popular race accompanies the half marathon for those seeking a shorter distance. Now in its forty-fourth edition, the event is an established fixture. Participants travel from across Valencia province and further afield, with prizes awarded to the top three male and female finishers.