In this work, we have described the use of sulfoanthranilic acid dithiocarbamate functionalized silver nanoparticles as a probe for simple, rapid and simultaneous colorimetric detection of Mn²⁺ and Cd²⁺ ions. The Mn²⁺ and Cd²⁺ ions induce the aggregation of sulfoanthranilic acid dithiocarbamate functionalized silver nanoparticles, resulting in a color change from yellow to orange associated with a red-shift in their surface plasmon resonance peak from 395 to 580 and 535 nm for Mn²⁺ and Cd²⁺ ions, respectively. Moreover, the aggregation of sulfoanthranilic acid dithiocarbamate functionalized silver nanoparticles induced by Mn²⁺ and Cd²⁺ ions was confirmed by dynamic light scattering and transmission electron microscopy. The Mn²⁺ and Cd²⁺ ion detection method based on their surface plasmon resonance peak using UV-visible spectrophotometry offers wide linear detection ranges from 5 to 50 μM and 10 to 100 μM with detection limits of 1.7 and 5.8 μM for Mn²⁺ and Cd²⁺ ions, respectively. The sulfoanthranilic acid dithiocarbamate functionalized silver nanoparticles act as a simple colorimetric probe for the simultaneous detection of Mn²⁺ and Cd²⁺ ions in various environmental water samples (drinking, tap, canal and river water) with good recovery values at minimal volumes of samples.