  We use the Weakly Interacting Massive Particle (WIMP) thermal decoupling
scenario to probe Cosmologies in dilatonic Einstein Gauss-Bonnet (dEGB)
gravity, where the Gauss-Bonnet term is non-minimally coupled to a scalar field
with vanishing potential. We put constraints on the model parameters when the
ensuing modified cosmological scenario drives the WIMP annihilation cross
section beyond the present bounds from DM indirect detection searches. In our
analysis we assumed WIMPs that annihilate to Standard Model particles through
an s-wave process. For the class of solutions that comply with WIMP indirect
detection bounds, we find that dEGB typically plays a mitigating role on the
scalar field dynamics at high temperature, slowing down the speed of its
evolution and reducing the enhancement of the Hubble constant compared to its
standard value. For such solutions, we observe that the corresponding boundary
conditions at high temperature correspond asymptotically to a vanishing
deceleration parameter q, so that the effect of dEGB is to add an accelerating
term that exactly cancels the deceleration predicted by General Relativity. The
bounds from WIMP indirect detection are nicely complementary to late-time
constraints from compact binary mergers. This suggest that it could be
interesting to use other Early Cosmology processes to probe the dEGB scenario.
