10 Best Coupler Lock of September 2025

• DIMENSIONS: 9” x 9” x 3”
• BUILT TO LAST: The REESE Towpower Universal Coupler lock is a premium lock constructed with an aluminum body and heavy-duty steel lock bar.
• UNIVERSAL FIT: Ratchet design is adjustable with 11 locking positions and fits 1-⅞”, 2”, and 2-5/16” couplers.
• DETERS THEFT: Bright, deterrent yellow color is durable, highly visible, and an essential accessory to all types of trailers.
• SECURE PROTECTION: Easy-to-install lock resists picking, prying and drill outs. Guards against truck or trailer towaway theft in storage.

Reese

• Universal coupler lock fits virtually all 1-7/8", 2", and 2-5/16" trailer couplers.
• This lock protects unattended trailers and guards against tow-away theft. The bright red finish discourages thiefs from messing with your trailer.
• Resists rust and corrosion. Simple installation and removal.
• Advanced locking mechanism resists picking and prying.
• We can NOT key two (2) of these locks the same. The similar 379KA coupler locks are available keyed alike. The only difference between this one (389DAT) and the 379KA is the color.

Master Lock

• Universal, fits all couplers
• Secures trailer when not being towed
• Ratchet design with eleven locking positions
• Fits 1-7/8, 2 and 2-5/16 inch trailers
• Two theft proof square keys are included

Reese

• DEPENDABLE SECURITY. To help protect your trailer from theft, this trailer lock is made from high-strength steel and has a padlock-style design
• EASY TO OPERATE. This padlock-style trailer tongue lock has a heavy-duty look to deter theft, and uses a simple 1/4-turn lock activation for convenient locking and unlocking as needed
• VERSATILE. With a 1/4-inch diameter pin, this trailer coupler lock fits latch-type couplers with a maximum span of up to 3/4 inches
• WEATHER-RESISTANT. This trailer pin lock is protected from the elements with its black painted finish, while the coupler pin is shielded against corrosion with a durable zinc plating
• TWO KEYS INCLUDED. For your convenience, two keys are included with this trailer tongue lock. You can keep the spare key in a discrete location for emergencies or give it to a friend for helpful access

CURT

• Designed to provide excellent towing
• Lockable offering extra safety
• Includes swiveling clip
• Includes swiveling clip
• Easy to install

Reese

• 6 locking positions
• Adjusts from 5/8 inch to 3 inches
• 3/16 inch diameter pin fits most couplers
• Flat key design
• Nickel plated steel shank and brushed aluminum body

Reese

• LOCK APPLICATION: Best used for vehicles, trailers, and RV hitch locks
• EASE OF USE: Six locking positions provide maximum flexibility; Rekeyable cylinder offers keyed-alike convenience
• DURABLE DESIGN: Water-tight cap protects trailer hitch lock from moisture and dirt
• SPECIFICATIONS: Coupler lock adjusts from 9/16 in. to 2-3/4 in. length
• INCLUDES: One trailer coupler latch lock, two keys

Master Lock

• Crafted from the highest quality material
• Perfect for outdoor and even indoor use
• Made in China
• One size fits all (from 1-7/8", 2", to 2-5/15", all coupler types)
• Key hole cover slides up to seal out dirt and grime
• Type A key which is a spring loaded, 7 pin, high security key. Resists attempted drill outs. Rugged and durable, the key will not bend or break.
• Huge 6 tooth, 3/8" dual ratchet locking system
• Hardened 5/8" 16mm steel shackle

Trimax

• This Master Lock protects and guards against tow-away theft. The lock works when the trailer is either connected to the tow vehicle or when the trailer is unattached. The lock prevents the coupler latch from moving, therefore preventing either the coupler to be removed from the ball, or not allowing a ball to be placed into the coupler.
• Fits UFP and surge brake couplers.
• Pin length or dimensional fit is 3-1/2" wide with a 9/32" diameter pin which is a standard size on virtually all couplers.
• Chrome plated for improved wear and corrosion resistance. It has a precision 4 pin tumbler mechanism that resists picking
• Weather Tough seal and water tight cap protects the lock from the elements

Master Lock

• Fits couplers with up to a 3/4" span
• Internal O-ring in lock keeps water, grime and dirt out of locking mechanism to ensure years of use
• Protective rubber cap protects keyhole from water, grime, and dirt
• Type A key which is a spring loaded, 7 pin, high security key. Resists attempted drill outs. Rugged and durable, the key will not bend or break
• Protective rubber bumper prevents rattling and abrasion

Trimax