This study investigates the breakup behavior of swirling liquid sheets discharged from gas-centered swirl coaxial atomizers, focusing on the role of the central gas jet. Cold flow experiments using water and air as fluids were conducted with custom-made atomizers. Photographic techniques were employed to capture the flow behavior of the liquid sheets under different flow conditions. The breakup length and spray width of the liquid sheets were quantitatively analyzed from the images. The central air jet significantly influences the sheet breakup process. Low inertia liquid sheets are more susceptible to the presence of the central air jet and develop shorter breakup lengths at lower air jet Reynolds numbers (Re_g). High inertia liquid sheets are less affected by the central air jet at lower Re_g values but eventually develop shorter breakup lengths at higher Re_g values. The central air jet causes surface corrugations on the liquid sheet, promoting the formation of thick liquid ligaments. The level of surface corrugations increases with increasing Re_g. Qualitative analysis suggests that the entrainment process between the inner surface of the liquid sheet and the central air jet is the primary trigger for sheet breakup. The study concludes that the breakup behavior of the liquid sheets is primarily determined by the flow parameters Weber number (We) and Re_g, with a more significant impact of Re_g on low inertia liquid sheets compared to high inertia liquid sheets.This study investigates the breakup behavior of swirling liquid sheets discharged from gas-centered swirl coaxial atomizers, focusing on the role of the central gas jet. Cold flow experiments using water and air as fluids were conducted with custom-made atomizers. Photographic techniques were employed to capture the flow behavior of the liquid sheets under different flow conditions. The breakup length and spray width of the liquid sheets were quantitatively analyzed from the images. The central air jet significantly influences the sheet breakup process. Low inertia liquid sheets are more susceptible to the presence of the central air jet and develop shorter breakup lengths at lower air jet Reynolds numbers (Re_g). High inertia liquid sheets are less affected by the central air jet at lower Re_g values but eventually develop shorter breakup lengths at higher Re_g values. The central air jet causes surface corrugations on the liquid sheet, promoting the formation of thick liquid ligaments. The level of surface corrugations increases with increasing Re_g. Qualitative analysis suggests that the entrainment process between the inner surface of the liquid sheet and the central air jet is the primary trigger for sheet breakup. The study concludes that the breakup behavior of the liquid sheets is primarily determined by the flow parameters Weber number (We) and Re_g, with a more significant impact of Re_g on low inertia liquid sheets compared to high inertia liquid sheets.