Guardamar del Segura is a municipality situated in the province of Alicante within the southern Valencia autonomous community of Spain. It lies at the mouth of the river Segura, positioning it as a Mediterranean resort town. The area is characterized by a large pine forest that abuts an eleven-kilometer-long white sand beach, defining its coastal geography.

Historically, the region served as a habitat for fishermen and farmers. The first settlement near the river mouth was a Phoenician colony known as Herna, recorded by the Roman geographer Avienius in his work Ora Maritima. The current name may derive from Valencian words meaning safekeeping and sea, reflecting its maritime location.

The town is notable for being the southernmost Valencian-speaking town and the only municipality in the Vega Baja del Segura comarca where Valencian is traditionally and widely spoken. Key landmarks include the Torreta de Guardamar, a radio mast that stands as the tallest military structure in the European Union, alongside its extensive coastal forests.

Guardamar hosts local festivals such as Moros i Cristianos, L'Encantà, and Fogueres de Sant Joan, which commemorate its history. The community maintains strong cultural traditions, with significant portions of residents speaking Valencian. These events and linguistic heritage draw visitors interested in the region's distinct cultural identity and historical roots.

The population was recorded at 18,564 as of 2025. Previous census data from 2006 showed 14,261 residents, rising to 16,863 by January 2011 before dropping to 15,589 in 2015. The town is governed by Mayor Carmen Verdú, who won the May 2011 municipal elections with an absolute majority for the People's Party.