  We simulate the dynamics of a single circle microswimmer exploring a
disordered array of fixed obstacles. The interplay of two different types of
randomness, quenched disorder and stochastic noise, is investigated to unravel
their impact on the transport properties. We compute lines of isodiffusivity as
a function of the rotational diffusion coefficient and the obstacle density. We
find that increasing noise or disorder tends to amplify diffusion, yet for
large randomness the competition leads to a strong suppression of transport. We
rationalize both the suppression and amplification of transport by comparing
the relevant time scales of the free motion to the mean period between
collisions with obstacles.
