What sets the beaches of Elche apart is the fact that they're virgin. The city is still a little ways from the beach so they are very well-preserved.
Elche has about 12 miles of coastline, not counting Santa Pola. The first of the coastal beaches in Elche is Playa de Altet and then Fondet of Senieta, both surrounded by dunes. These two beaches are beautiful and totally virgin...you even need to make a good hike across the dunes to reach them.
Then you have the Playa de Arenales del Sol. It's nice, but it's the only beach in Elche that has any kind of urban build-up. After a long walk down Arenales del Sol, you reach Playa de Carabassi, the most popular beach in Elche. It's a stunning, long beach with many dunes and a nudist area. Afterwards, you reach Escull beach, the only rocky beach in Elche. This marks the end of the Elche beaches and the beginning of Santa Pola.