The presence of two endemic Sargassum spp., Sargassum filipendula and Sargassum vulgare, along the eastern coasts of Trinidad and Tobago were investigated to assess the pollution status of those localities. Heavy metal and polycyclic aromatic hydrocarbon (PAHs) concentrations in these marine organisms were determined. Average concentrations of Cd, Cu, Fe, Mn, Ni, Pb, and Zn were 4.59, 5.05, 744.98, 69.10, 8.33, 8.59, and 24.30 μg g−1 (dry wt.) in S. filipendula and 1.81, 8.82, 114.11, 24.18, 9.84, 7.05, and 119.46 μg g−1 (dry wt.) in S. vulgare, respectively. Metal pollution indices were established for each location. Total PAH concentrations (Σ16 PAHs) ranged from 287.4 ng g−1 in S. filipendula (Mayaro) to 605.1 ng g−1 in S. vulgare (Speyside). The use of PAH diagnostic ratios, principal component analysis, and cluster analysis were used for source identification of PAHs in each of the Sargassum spp. from the various regions. It was concluded that these Sargassum spp. can be utilized as biomarkers for heavy metals and PAHs in the surrounding waters of Trinidad and Tobago.