The revolution of growing urban population and complicity of the city’s vast amounts of operations has resulted in the establishment of a smart city—one that utilizes the current state-of-the-art technology to enhance the quality of life of the consumers and streamline the use of its resources. However, the smart city faces significant security, privacy, and trust issues due to numerous interconnected systems handling vast amounts of sensitive data. Blockchains developed as a decentralized, transparent, and immutable technology, can solve these issues and revolutionize the vast number of applications of contemporary smart cities. This paper outlines how blockchains can form a basis for the secure and effective deployment of multiple smart city solutions, covering a diverse set of applications, including data management, energy trading, transportation, waste handling, and digital identity. It explains the advantages that blockchains offer, which include increased security, transparency, efficiency, and decentralized decision-making. At the same time, the paper highlights the existing challenges and considerations with the adoption of blockchain for smart cities, such as lack of scalability and regulation, insufficient interoperability, high energy consumption, and low public awareness. Finally, it provides recommendations for their successful deployment and stresses the need for future research and cooperation to enable the full potential of blockchains for safe, effective, and user-driven smart cities.