  In this paper, we find a two-parameter family of coupled Painlev\'e systems
in dimension four with affine Weyl group symmetry of type $D_3^{(2)}$. We also
find a four-parameter family of 2-coupled $D_3^{(2)}$-systems in dimension
eight with affine Weyl group symmetry of type $D_5^{(2)}$. We show that for
each system, we give its symmetry and holomorphy conditions, respectively.
These symmetries, holomorphy conditions and invariant divisors are new.
