This book chapter delves into the realm of IoT communication technologies, exploring the diverse array of wireless and wired options that enable devices to connect and exchange data.From well-known technologies like Wi-Fi and Bluetooth to Zigbee, Z-Wave, LoRaWAN, and cellular-based technologies such as NB-IoT and LTE-M, this chapter explores their features, characteristics, and applications in the world of the Internet of Things. Additionally, it covers essential IoT protocols like MQTT, CoAP, HTTP, and AMQP, emphasizing their role in facilitating data transfer and messaging in IoT environments while addressing critical security considerations. The chapter concludes by examining future trends that promise to further elevate IoT connectivity, including 5G integration, edge computing, AI, and blockchain