Loss characteristics of potassium and silver double‐ion‐exchanged glass waveguides are studied. Low propagation losses (less than 0.25 dB/cm) at 1.296 &mgr;m wavelength are measured, although aluminum as a mask and inexpensive multipurpose glass as a substrate are used in the fabrication process. The losses are compared to the losses of waveguides made by one‐step aluminum masked silver ion exchange and by silver ion exchange with ionic masking (dielectric mask). The reasons for the loss reduction in double‐ion‐exchanged waveguides compared to one‐step silver ion‐exchanged waveguides are discussed.