Malaysia lies within the East Asian-Australasian Flyway (EAAF), among the world's most species-rich and threatened flyways, which provides stop-over sites for millions of passages and wintering birds. Although some mudflats along the west coast of Peninsular Malaysia are classified as Important Bird and Biodiversity Areas (IBA), no detailed studies have been conducted to compare shorebird composition and diversity between these locations. Hence, the species composition and diversity of shorebirds was assessed in established plots on mudflats of the North-central Selangor Coast (NCSC) and Teluk Air Tawar Kuala Muda Coast (TAT-KMC) between December 2022 and January 2023. A total of 31 species from three families, Charadriidae, Scolopacidae, and Laridae, were documented throughout the study. There was a significant difference in shorebird species composition between the two sites. TAT-KMC recorded more threatened species including the Far Eastern Curlew Numenius madagascariensis and Nordmann's Greenshank Tringa guttifer. Despite the presence of more threatened species at TAT-KMC, the results showed both stop-over sites are important for migratory shorebirds along EAAF. The data obtained are valuable for assessing the current species richness and abundance, highlighting the importance for these IBAs to be designated as another Flyway Site Network representing west coast Peninsular Malaysia in order to enhance their protection and conservation efforts.