Mobile Number Portability (MNP) as a regulatory requirement for Mobile Network Operators (MNO), allows users to easily switch their operators while keeping their number. User subscription, profile management, and MNP procedures in current MNOs are handled in centralized systems and databases that rely on trusted third parties. Having a single point of failure, low scalability, high latency, imposed porting fees, data leakage in the central database, low availability, and need for re-subscription while porting procedure are the most highlighted defects of the conventional systems. Addressing these issues, we propose a Blockchain-based system to 1) manage user subscription and user profile/identity in a distributed database, and 2) mobile number and profile porting procedure. This solution eliminates any central point via managing the processes using smart contracts. Moreover, it decreases IT complexity, increases automation, provides low latency, and high confidentiality. The experiments confirm that this solution can provide fast and scalable profile management and porting solution.