There is restriction on the usage of mobile phone in certain potentially dangerous premises such as petrol station and hospital. The usage of mobile phones at those premises might cause some disturbances and hazards. Therefore, safety precautions need to be taken into consideration when we are within the premises. Unfortunately, there are still many users who disobey the rules and use their mobile phone in those areas. Therefore, mobile phone detector is used to monitor the usage in the premises. Thus, software approach is implemented. The design of this location-based safety alert system will make the smartphone to intelligently detect the user’s location all the time after it is activated. It will alert and ask the user to switch to airplane mode once the system detects the user is in those premises. Thus, the safety alert system not only acts as a reminder to reduce the chance of the accidents occurring to the user itself, but also allocate a safer surrounding to the public.