Mobile Number Portability (MNP) is an ability of changing operator (porting) without changing the number. This scheme provides freedom and convenience for customers to get the best services. This scheme allows the regulator to gain efficiency of block number as a limited resource. Analysis in this research consisted of techno-economic analysis to provide options for the operator (Telkomsel) and RIA (Regulatory Impact Analysis) for the regulator. The output from these two analyses were processed and simulated based on customer behavioral data to obtain the impact of MNP. Both analyses indicated that market operators did not change drastically after MNP implementation. On Telkomsel, number of customers who port-in exceeds the port-out (48% against 43%). RIA analysis showed that the benefits received by the public exceeded the cost incurred.