For that, you’d want a coupler lock. These U-shaped locks fit over the coupler on the trailer’s tongue and prevents someone else from hooking up his vehicle to your trailer. Many have ball-shaped tops to go where the ball unit on your vehicle would normally go into the coupler.

Why do you need a trailer coupler lock?

A coupler hitch lock can be used to protect your trailer from being stolen whether it’s hitched to your vehicle or unhitched. The U-shaped lock makes it difficult for someone without the key to hook their towing vehicle into the hitch because it fits over the coupler on your trailer’s tongue.

What is the most secure trailer coupler lock?

• REESE 72783 Universal Coupler Heavy-Duty Lock.
• AMPLOCK U-BRP2516 RV/Trailer Coupler Lock.
• Master Lock 389DAT Universal Size Trailer Lock.
• Master Lock 2866DAT Swivel Head Receiver Lock.
• Master Lock Receiver and Coupler Lock Combo.