The Zwicky Transient Facility Data Release 2 (ZTF DR2) includes a total of 3628 Type Ia supernovae (SNe Ia), providing the largest and most complete sample of spectroscopically confirmed SNe Ia at low redshift to date. In this paper, we present a photometric and spectroscopic analysis of 124 subluminous SNe Ia, the largest sample of spectroscopically classified subluminous type Ia supernova observed with a single instrument, comprising 87 91bg-like, 12 86G-like, 18 04gs-like, and 7 02es-like events. We complement the published DR2 SALT2 light-curve parameters with new parameters obtained using template-based fits from SNooPy. Expansion velocities and pseudo-equivalent widths pEW of key spectral features are measured using Spextractor, and spectral averages are constructed for each subluminous subtype, binned by phase. We also analyze the host galaxy environments, both global and local, in terms of g-z color, stellar mass, and directional light radius d_DLR_. We find that all subluminous SNe~Ia (except the 02es-like subtype) are intrinsically red. This is evident by separating extrinsic from intrinsic color components. Since SALT2 is not trained on subluminous SNe Ia, it compensates for their redder colors by inflating the c parameter, thus extending the luminosity- width relation to negative values of x1. As expected, all subluminous SNe Ia fall within the Cool region of the Branch et al. (2006PASP..118..560B) diagram, with the exception of 02es-like events, which show lower SiII 5972 pEW values. All subluminous subtypes tend to occur in more massive, redder host galaxies, and in the reddest local environments within their stellar mass bins. Notably, 91bg- and 86G-like SNe Ia explode at significantly larger normalized galactocentric distances. Finally, we identify the $pEW$ of the blended TiII+ SiII+MgII absorption feature at 4300{AA}, along with s_BV_, as robust and sufficient indicators for subclassifying subluminous SNe Ia.

Cone search capability for table J/A+A/707/A91/tablea1 (SN Ia light-curve parameters)