This study was conducted to supplement information on the fluctuation of some morphological characteristics for species identification of Tubuca rhizophorae in some coastal provinces of the Mekong Delta. A total of 407 individuals (296 males and 111 females) were collected by hand in Bac Lieu and Ca Mau provinces from January 2024 to April 2024. The analysis results showed that Tubuca rhizophorae exhibited differences in manus width (MW3), pollex width (PW5), and dactyl width (DW7) between the two sampling sites (p<0.05). Specifically, MW3, PW5, DW7 values in Ca Mau and Bac Lieu were 1.55±0.01 and 1.62±0.02; 0.54±0.01 and 0.59±0.01; 0.48±0.01 and 0.53±0.01, respectively. Similarly, carapace width [CW(L-R) and CW(R-L)] and manus width (MW2) showed significant change with sex (p<0.05). Specifically, CW(L-R), CW(R-L), and MW2 of females and males were 12.30±0.10 and 12.99±0.08; 12.31±0.09 and 12.93±0.08; 1.03±0.02 and 1.17±0.03, respectively. The results also noted that environmental factors such as temperature, salinity, and pH displayed a positive relationship with morphological trait variations of this species.