  We consider the extension of the Standard Model with scalar leptoquarks as a
portal to dark matter (DM), motivated by the recent anomalies in semi-leptonic
$B$-meson decays. Taking singlet and triplet scalar leptoquarks as the best
scenarios for explaining $B$-meson anomalies, we discuss the phenomenological
constraints from rare meson decays, muon $(g-2)_\mu$, and leptoquark searches
at the Large Hadron Collider (LHC). Introducing leptoquark couplings to scalar
dark matter, we find that the DM annihilations into a pair of leptoquarks open
a wide parameter space, being compatible with XENON1T bound, and show that
there is an interesting interplay between LHC leptoquark searches and distinct
signatures from cascade annihilations of dark matter.
