Antimony (Sb) leaching from polyethylene terephthalate (PET) bottling material was assessed in eight registered Lebanese brands of bottled natural water as a function of contact time. The study was performed indoors at 22 °C in the dark and outdoors at a maximum temperature of 45 °C under sunlight. The leached antimony concentration increased with contact time for all of the studied brands except one. The antimony concentration reached 5.5 μg/L after 544 days of contact time with PET packaging. Small bottles with large contact surface area had higher antimony concentration. However, outdoor storage under sunlight at temperatures below 45 °C did not reveal a significant effect on antimony release. Among some physico-chemical parameters studied (pH, calcium, magnesium and bicarbonate), only calcium concentration showed a significant effect on antimony release. The rate of antimony leaching, normalized to the surface to volume ratio of the water bottle, fits the exponential model Sb/(S/V) = 0.562e^0.0041t, with R² = 0.87. Atomic absorption spectroscopy analysis of the different PET packaging material showed an antimony concentration between 80.6 and 352.7 mg Sb/kg PET.