No! Often you don't need any equipment to perform isometric exercises.
The Simple Truth
Isometric exercises are about holding a static position and creating tension without movement. This makes them perfect for using just your own body and/or common objects around you.
Equipment-Free Examples:
Isometric Push Up: Just your body and the floor.
Wall Sit: All you need is a sturdy wall.
Glute Bridge: Just you and the floor
When Equipment Might Be Used:
While not essential, things like straps for overcoming isometric exercises (e.g., pulling against an anchored strap) can increase intensity or offer more variety in your isometric training.
Bottom Line:
You can build significant strength and stability with isometric exercises using nothing but your body and your surroundings which makes the a simple, safe and convenient way to stay in shape!