High toxicity and widespread availability of fluoride ions in different environmental matrices prompted attention for designing an efficient probe for its detection. Given this, a new sensor based on coumarin 343 (C343) dye and Eu3+ is designed and working mechanism of probe was understood using steady state optical absorption and emission and time resolved emission studies. The designed probe is free of tedious synthetic procedure and sophisticated instrumentation and is highly selective. A general procedure is designed for fluoride ion detection in samples and it was observed that fluoride ion concentration well below 2 ppm can be detected visually, a limit set by WHO for fluoride ion in drinking water. The suggested probe was also tested for fluoride ion concentration in the real sample and it was observed that the result matches well with the values obtained from standard technique. The designed probe is economical, rapid, selective and most importantly can be used directly for fluoride ion determination in real aqueous samples.