Avicennia marina forests fulfill essential blue carbon and ecosystem services, including halting coastal erosion and supporting fisheries. They endure high abiotic stress to inhabit a broad range of Indo-Pacific coastlines; despite human dependence and serving as model halotolerant angiosperms, genetic studies are scarce for this organism. We compare transcriptomes from A. marina roots, stems, leaves, flowers, seeds, and transcriptomes across four widely divergent environments in the Indo-Pacific (Red Sea, Arabian Gulf, Bay of Bengal, Red River Delta) to decipher shared and location-, tissue- and condition-specific functions. On average, 4.8% of transcripts per tissue were uniquely expressed in that tissue, and 12.2% were shared in all five tissues. Flowers’ transcript expression was the most unlike the other tissues, and domain-centric gene ontology analysis showed heavy enrichment towards various stimulus-responsive processes. Tissue-specific metabolic pathway reconstruction revealed unique processes in the five tissues; for example, flowers showed evidence of only fatty acid biosynthesis but stems expressed only fatty acid degradation enzymes. The leaf transcriptome had the lowest functional diversity among expressed genes in any tissue. Metallothioneins (MTs) were the highest-expressed genes in all tissues and from specimens of all locations; the dominant expression of these metal-binding and oxidative-stress control genes indicates they are essential for A. marina in its natural habitats. Our study lays a foundation for tissue-specific A. marina transcriptomes and how they support its resilient, seafaring lifestyle.