This species typically grows in the intertidal regions of sheltered tropical and subtropical coasts (Saenger 2002). It typically dominates the zone proximal to open water (McKee 1995). It grows as a shrub to small tree from 1-8 m in the Caribbean (Howard 1989) and can be reproductively mature at <1 m (Tomlinson 1986). This species is typically found from 20-35 psu. However, it can occur in brackish estuarine systems as well as in hypersaline conditions (50+ psu) where the growth form is commonly dwarf (1-2 m).

In Port Royal (17°56'N, 76°79'W), R. mangle grows in a dense monospecific stands, bordering all wetland water bodies. It is also present in a mixed zone between the R. mangle monospecific stands and monospecific stands of C. erectus, which is the border between the wetland and terrestrial zones (Alleng 1998).

Flowering occurs annually in mid-winter and spring within the wider Caribbean. Propagule size can be variable, shown to be larger in areas of higher rainfall (Tyagi 2003). Production of viviparous propagules is abundant and maintained on the parent tree for 3-6 months. Once dropped, propagules can subsist for extended periods afloat prior to rooting. Successful growth requires a canopy break or transport to open area to grow to maturity.

Fringing R. mangle (in association with seagrass beds) provide critical for Caribbean parotfish (Scarus guacamaia), a species listed as vulnerable on the Red Data List. This species is also associated with stabilization of sandy beaches critical for sea turtle nesting habitat, among countless other critical habitat functions.