Halophyte plants can grow and reproduce in hostile environments, such as areas with high drought, intense light exposure, extreme cold or heat and high salinity. These plants possess special mechanisms allowing them to grow and reproduce under such conditions, which can be categorized into anatomical structures and their potent antioxidant system. The collection of halophyte plants from two different sites is relevant for understanding potential variations in their chemical profiles. Phytochemical screening plays an important role in examining unique characteristics of specific plants or extracts. The presence or absence of a wide range of phytochemical groups, such as carbohydrates, terpenoids, flavonoids, reducing sugars, and phenolic compounds, was assessed, to compare plants collected from two different sites. Halophyte plants are gaining popularity due to their potential uses in various industries, yet the presence or absence of these phytochemical groups remains insufficiently explored. Depending on the identification processes and the type of extract required, several tests were conducted for specific compounds. For instance, both methanolic and aqueous extracts may be required for assays targeting the same compound group. The results revealed distinct profiles, with only minor differences observed between the same plant species collected in Setúbal (Sado Estuary) and in Alcochete (Tagus Estuary). For example carbohydrates, according with Molish’s test, were detected in samples from the Sado Estuary but not in those from the Tagus Estuary. While preliminary, these findings offer valuable insights into the chemical composition of specific plant species and their potential applications.