We have theoretically investigated the intrinsic carrier mobility in semimetals with tilted Dirac cones under both longitudinal and transverse acoustic phonon scattering. An analytical formula for the carrier mobility was obtained. It shows that tilting significantly reduces the mobility. The theory was then applied to 8B-Pmmn borophene and borophane (fully hydrogenated borophene), both of which have tilted Dirac cones. The predicted carrier mobilities in 8B-Pmmn borophene at room temperature are 14.8 × 105 and 28.4 × 105 cm2 V-1 s-1 along the x and y directions, respectively, both of which are higher than that in graphene. For borophane, despite its superhigh Fermi velocity, the carrier mobility is lower than that in 8B-Pmmn owing to its smaller elastic constant under shear strain.