The main difference between Static NAT and Hide NAT lies in the directionality of the connections they allow. Static NAT allows both incoming and outgoing connections because it maps a single private IP address to a single public IP address, enabling the same IP address to be used for both types of connections. On the other hand, Hide NAT, also known as PAT (Port Address Translation), only allows outgoing connections by mapping multiple private IP addresses to a single public IP address, thus effectively hiding multiple hosts behind a single IP address when they initiate outbound communication.