  The Belle II experiment at the SuperKEKB energy-asymmetric $e^+ e^-$ collider
is a substantial upgrade of the B factory facility at the Japanese KEK
laboratory. The design luminosity of the machine is $8\times 10^{35}$
cm$^{-2}$s$^{-1}$ and the Belle II experiment aims to record 50 ab$^{-1}$ of
data, a factor of 50 more than its predecessor. From February to July 2018, the
machine has completed a commissioning run, achieved a peak luminosity of
$5.5\times 10^{33}$ cm$^{-2}$s$^{-1}$, and Belle II has recorded a data sample
of about 0.5 fb$^{-1}$. Main operation of SuperKEKB has started in March 2019.
Already this early data set with specifically designed triggers offers the
possibility to search for a large variety of dark sector particles in the GeV
mass range complementary to the Large Hadron Collider (LHC) and dedicated low
energy experiments; these searches will benefit from more data in the process
of being accumulated. This talk will review the state of the dark sector
searches at Belle II with a focus on the discovery potential of the early data,
and show the first results.
