  We study AdS duals of four-dimensional (4D) $\mathcal{N}=1$ superconformal
field theories (SCFTs) on $\mathbb{Z}_k$ S-folds with T-branes that flow to 4D
$\mathcal{N}=3$ theories. In a previous study, it was discussed how considering
T-brane structure breaks the $\mathcal{N}=2$ supersymmetry in 4D SCFTs on
$\mathbb{Z}_k$ S-folds down to $\mathcal{N}=1$. In this study, we analyze this
effect from the AdS perspective. We also discuss the constructions of 4D
$\mathcal{N}=1$ SCFTs on S-folds with T-branes starting from global K3
hypersurfaces whose fibers involve complex multiplications. We choose an
approach to directly analyze the global K3 geometry without relying on the
standard Weierstrass technique.
