Swimming is prohibited in the sea after sunset mainly due to safety concerns. At night, certain marine creatures become active, and swimming in darkness can pose risks to swimmers. These creatures may be dangerous, and visibility is significantly reduced, making it hard to see potential hazards. In hotel swimming pools, swimming is restricted after sunset because chemicals, such as chlorine, are often added to the water at night. These chemicals can be harmful to the skin if swimmers are exposed to them before they properly dissolve and interact with the water. Overall, swimming is banned in both settings during the evening for safety reasons, particularly due to the absence of lifeguards who are typically on duty during the day to respond to emergencies.