Water is one of the essential requirements for human life. Various types of impurities that are present in the drinking water can produce grave health concerns, affect body tissues, and may lead to death. Protozoan parasites are one of the major biological pollutants in the water, which are ordinarily transferred across during the oral-fecal path. Cryptosporidium parvum oocysts (CPO) and Giardia lamblia (GL) are two frequently observed waterborne protozoan organisms. They have different values of index of refraction (IOR). Novel detector can be established with real-time detection based on this biophysical consideration. Here, an optical surface plasmon resonance biosensor (OSPRB) is developed for discovery of CPO and GL in drinking water. Angular examination and Kretschmann design are employed to explain the conception of the setup. An angular sensitivity (AS) of 188 Deg./RIU is attained by the suggested OSPRB with very low limit of detection (LOD) of 2.64 × 10−5 RIU. Other functioning factors are calculated for offered OSPRB. The achieved outcomes indicate that the suggested OSPRB has conspicuously improved performance as contrasted to aforementioned outcomes in the literatures. The suggested OSPRB can accelerate a substantial biological detecting tool with accurate and fast sensing at early point.