Abstract: This study investigated the seismic performance of precast seawater sea-sand concrete (SWSSC) beam-column exterior joints with two connection types (U-shaped BFRP dowel bar connection and BFRP beam-bar anchoring connection) through experimental comparison between cast-in-situ steel-reinforced ordinary concrete joints and cast-in-situ BFRP-reinforced SWSSC joints. The experimental results indicated that all four specimens failed in flexure at the beam end. The joint with U-shaped BFRP dowel bars demonstrated reliable performance, while the joint with directly anchored BFRP bars exhibited behavior comparable to the cast-in-situ specimen at low to medium drift levels, but was prone to developing a through-type crack under high drifts. The peak strengths of the two precast BFRP-reinforced SWSSC joints were 4.3% and 4.7% lower, respectively, and their stiffness were 10.3% to 38.4% lower than that of the cast-in-situ BFRP-reinforced SWSSC joint. However, all the three SWSSC joints showed similar energy dissipation capacity, with average equivalent damping ratios of 0.23, 0.22, and 0.22, respectively, indicating that the two proposed precast connections met the design principle of "equivalent cast-in-situ" performance. Furthermore, a mechanical model for the BFRP-reinforced SWSSC beam-column joint was established based on equilibrium and compatibility conditions using the softened strut-and-tie mode. The failure mode of the joint was predicted by comparing the shear capacity calculated from the softened strut-and-tie model with the flexural capacity at the beam end. The experimental results validated the accuracy of this failure mode prediction method based on capacity comparison. The softened strut-and-tie model provided a theoretical basis for the shear design of BFRP-reinforced SWSSC beam-column joints.