Searching for brings up many shady torrent sites. Let's clarify the legality.
You still need your original CD Keys (Reign of Chaos and The Frozen Throne) to install and launch these versions. Installation: Download the full 1.31 client (installer or zip).
→ You need Reforged (version 1.32+). Sorry. Download Warcraft 3 Frozen Throne 1.31
If you own a classic key, you can download the modern launcher. Note that this will force you into the Reforged engine (though you can play with "Classic" graphics toggled on). Easy setup, official multiplayer servers. Very large file size (~30GB), lacks the original 2003 UI. 2. Public Test Realm (PTR) Installers
: A popular choice for CIS-region players that provides a specific 1.31 installer and instructions to play on private servers. Searching for brings up many shady torrent sites
Because Blizzard's official Battle.net launcher now automatically forces the Reforged update, obtaining the specific 1.31 classic client requires using legacy installers or community archives. 1. Official Legacy Installers (Requires CD Keys)
Whether you're looking to relive the original campaign without the Reforged changes or want to play custom maps that are only compatible with the classic engine, here is everything you need to know about downloading and installing version 1.31. Why Version 1.31? Installation: Download the full 1
Once launched, check the bottom-right corner of the main menu. You should see: