Tungsten (W) offers exceptional high-temperature strength, but its ductile-to-brittle transition temperature (DBTT) lies above room temperature, limiting its formability. Alloying with rhenium (Re) improves ductility, though the dislocation mechanisms responsible are not fully understood. In this work, we extend the phase-field dislocation dynamics (PFDD) model to treat {112}〈111〉 dislocations in body-centered-cubic crystals and simulate thermally activated glide of screw and edge dislocations in W and W-20%Re at temperatures spanning their DBTT. In both materials, the critical resolved shear stress is higher for {112} glide than for {110} glide, and the {112} twinning/antitwinning asymmetry vanishes at a lower temperature in W-20%Re than in pure W. Re increases the activation enthalpy for screw dislocation glide on {110} planes but decreases it on {112} planes, suggesting that Re additions shift slip activity from primarily {110} slip to both {110} and {112} slip.