3D-printed syntactic foams have advantages over traditionally fabricated foams such as design flexibility, in-field fabrication and low investment cost. Current 3D printing methods developed for thermoplastic syntactic foams suffer from unavoidable porosity and low mechanical performance. In this study, we overcame these limitations by fabricating thermoset-based syntactic foams using direct-write 3D printing which allowed us to fabricate buoyant syntactic foams with unprecedented strength (> 100 MPa) and modulus (1.2 GPa). This study also showed that the mechanical performance of these materials can be tailored by reinforcing the thermoset foams via milled carbon fibers. 3D-printed thermoset-based syntactic foams with high scalability and tailored mechanical performance have great potential to find immediate applications where weight reduction, mechanical performance and component complexity are desired.