How to Switch Minecraft to Borderless Fullscreen

Using the In-Game Toggle

Once the mod is installed, you do not need to edit any files to get borderless mode working. Launch the game and open Options > Video Settings. Look for the fullscreen toggle that the mod adds or replaces. Clicking it will switch the game from a windowed state directly into borderless fullscreen, which fills your monitor without drawing a title bar or resize handles.

If you prefer the keyboard, the standard fullscreen hotkey still works and will now trigger the borderless behavior instead of the vanilla exclusive fullscreen. Press it once to enter borderless, and press it again to drop back to a window.

Confirming It Worked

A quick way to verify borderless mode is active: move your mouse to the very top edge of the screen. In vanilla fullscreen the game grabs the cursor and you cannot reach other windows. In borderless mode the cursor can leave the game area, and alt-tabbing or clicking another window happens instantly without the screen flashing black.

If the game still behaves like old fullscreen, make sure no other display mod is overriding the setting, then toggle fullscreen off and back on. Borderless mode should persist between launches once enabled.