ICQ Alternatives for Mac OS X

Skype is a versatile communication platform offering free voice and video calls to other Skype users, as well as affordable calls to landlines and mobile phones worldwide. It provides instant messaging, file sharing, and screen sharing features, making it a comprehensive tool for personal and professional connectivity across various devices.

Pidgin is a free and open-source multi-protocol instant messaging client designed to connect users across various chat networks with a single application. It's highly extensible through plugins and supports a wide range of protocols including XMPP, ICQ, and IRC.

Telegram is a fast and secure cloud-based instant messaging platform offering robust privacy features, large group support, file sharing, and cross-platform synchronization, making it a versatile communication tool.

WhatsApp Messenger is a widely used free messaging and calling app, available globally. It enables communication through text, voice messages, and video calls, facilitating connections between individuals and groups across various devices and platforms.

Adium is a free and open-source instant messaging client for macOS, designed to connect to multiple chat networks simultaneously. Supporting protocols like Jabber (XMPP), Google Talk, AOL Instant Messenger (AIM), ICQ, MSN Messenger, and Yahoo! Messenger, Adium provides a unified interface for all your conversations.

Tox is a free, open-source, and secure peer-to-peer instant messaging and video calling protocol designed for strong privacy and censorship resistance. It provides end-to-end encrypted communications without reliance on central servers.

Trillian is a versatile, multi-protocol instant messaging client that unifies various communication platforms like IRC, XMPP, and more into a single, user-friendly interface. It's designed for both personal and team collaboration, offering features like encrypted chats, group collaboration tools, and extensive customization options.

Viber is a comprehensive messaging and VoIP application enabling free and secure calls and messages to users worldwide. It offers robust features for both individual and group communication across various devices.

Signal is a secure, open-source messaging application that uses end-to-end encryption to protect user communications. It offers text messaging, voice and video calls, group chats, and file sharing, all with a strong focus on privacy and security. Available on multiple platforms, Signal is a leading choice for individuals prioritizing confidential conversations.

Psi is a robust, open-source instant messaging client built on the XMPP protocol. It's known for its focus on speed, efficiency, and adherence to XMPP standards, offering a clean interface and strong privacy features for secure and reliable communication.

Kopete is a versatile, free and open-source instant messaging client designed initially for the KDE Plasma desktop. It distinguishes itself by supporting a multitude of protocols, allowing users to connect to various chat networks from a single application.

WeChat is a comprehensive mobile app offering instant messaging, social networking, payment services, and access to a wide range of mini-programs. It facilitates communication through text, voice, and video, supports group interactions, and integrates various lifestyle services.

Instantbird is a powerful, cross-platform instant messaging client built on Mozilla's XULRunner, leveraging the robust libpurple library from Pidgin. It supports a wide array of instant messaging protocols, offering a unified chat experience.

qutIM is a free and open-source, multi-protocol instant messenger designed for connecting to various networks including ICQ, Jabber, Mail.Ru, IRC, and VKontakte. It offers a unified interface for managing multiple accounts and conversations.

KakaoTalk is a popular mobile messaging service offering free text, voice, and video calls. Primarily used in South Korea, it provides a comprehensive communication platform with features like group chats, stickers, and a strong emphasis on user privacy and security.

Zulip is a powerful open-source group chat application designed for team collaboration. It uniquely structures conversations around topics, enabling users to easily catch up on important discussions and manage information overload. Zulip facilitates secure communication with integrated file sharing and various integrations.

Dialog Messenger is a robust, feature-rich enterprise messaging solution designed for businesses prioritizing security, privacy, and control. Available for both private server deployment and cloud hosting, it facilitates secure text, voice, and video communication across multiple devices, enabling seamless collaboration and real-time interaction within organizations.