Best Rated Trailer Coupler Lock

Jessica McDaniel
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If you park your trailer in a public lot, chances are you know how valuable a quality trailer coupler lock can be.

I personally can attest to the value of a good trailer coupler lock. I live in a neighborhood that has a large number of RV’s that are exposed to the elements of the outdoors and unfortunately, people tend to forget they aren’t the only ones who have the access keys to their RV’s.

I’ve heard a number of stories from friends who’ve had their trailers broken into while left unattended.

And if you think the only issue is theft, you’re in for a rude awakening.

Master LockBest OverallMaster Lock
Master Lock 377KA Trailer Hitch LockBudget PickMaster Lock 377KA Trailer Hitch Lock
Trimax UMAX100 Premium Universal 'Solid Hardened Steel' Trailer LockUpgrade PickTrimax UMAX100 Premium Universal 'Solid Hardened Steel' Trailer Lock

1. Master Lock

Our rating: 9 / 10

Master Lock

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  • Secured with patented bolt protection for better theft deterrence
  • Easy to install
  • Lock the back-wheel axle
  • Protect yourself from your junk being stolen


  • Cannot protect the entire trailer
  • Requires a little effort to install
  • Expensive

If you plan on parking your trailer outdoors, it’s important to take care of it. Nothing is worse than coming back to see your entire life being carried away on the back of a truck.

The Master Lock 389DAT is called a universal trailer coupler lock, but it’s more of a comprehensive security solution than a coupler lock.

If you want your trailer to be as protected as it can get, you’d use this lock with a chain and padlock. The 389DAT is universal, so you don’t need to worry about it fitting your trailer.

2. Master Lock 377KA Trailer Hitch Lock

Our rating: 9 / 10

Master Lock 377KA Trailer Hitch Lock

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  • Stable enough to hold any job
  • Thick steel plate
  • Sturdy and dependable construction
  • Affordable

The Master Lock 377KA Trailer Hitch Lock is a device made for ensuring your trailer staying where you want it. It will latch firmly to your trailer hitch to make it impossible for a thief to damage it. Just like any other hitch lock, it is suitable for locking the trailer hitch ball of most trailers.

For as long as you have your Master Lock 377KA Trailer Hitch Lock, you will not have to worry about the safety of your trailer. It has a solid steel construction which prevents it from being damaged. This hitch lock fits 1-7/8in. 2 in. and most 2.5 in trailer coupler and although it is recommended to use locks which are made specifically for the trailer hitch coupler, the Master Lock 377KA Trailer Hitch Lock is mostly constructed out of steel, which prevents it from being damaged and it can successfully prevent theft if used correctly.

The length of the locking shank is 1/4 inches thick and the pin tumblers are called T-C106 which takes the guessing out of how to open the hitch pin lock because it is already in the instructions.

3. Trimax UMAX100 Premium Universal 'Solid Hardened Steel' Trailer Lock

Our rating: 9 / 10

Trimax UMAX100 Premium Universal 'Solid Hardened Steel' Trailer Lock

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  • Universal
  • 1 Year Money Back Guarantee

When it comes trailer coupler locks they’re basically all the same with the same functionalities.

There’s just one difference between them: some of them’re universal while others are designed as replacement.

The Trimax UMAX100 is a universal trailer coupler lock that fits any kind of trailer coupler. It’s made from solid hard steel and weighs 2.8 pounds which are the most common trailer coupler locks.

4. Blaylock TL-33 Coupler Lock

Our rating: 8 / 10

Blaylock TL-33 Coupler Lock

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  • Great appearance
  • Easy to use and install
  • Cheap in terms of price
  • Ideal for trailers with ball couplings
  • Uses a three-digit combination
  • Perfect for extra security of your trailer
  • Reliable lock style


  • The optimal number of digits for the lock should be more
  • Needs a lot of physical strength to use the lock

The Blaylock Coupler Lock is a great choice if you want the trailer hitch lock to serve its basic function. It has a reliable lock mechanism and the ability to use a variable 3-dial combination to keep it from being picked by any thief.

It has an appropriate size and weight and can be really useful for trailers with ball couplings. It’s very easy to use and install, so you don’t have to worry about taking much time to install the lock. Just read the use manual carefully and install it accordingly. It is a strong lock, and the number of digits that you can possible use is 2,000.

This is a durable lock that will last you a lifetime if you take good care of it and use it carefully. However, using the lock will take a lot of strength because you have to utilize it manually. It also has a good appearance in the overall design.

5. Tow Ready

Our rating: 8 / 10

Tow Ready

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  • Lock your trailer to prevent theft
  • Easy to install and use
  • Durable

The main reason you need a hitch coupler is to attach your trailer and to transport things with it. However, as you will drive down the road, there’s always a risk that someone will detach your trailer and leave with it.

The Tow-Ready 63228 provides a solid solution to this as it will prevent anyone from stealing your trailer. Especially if you’re somewhere in the back roads of the country. Which is where you’re most likely to have a problem with having your trailer stolen.

It has a permanent pin attached to the body of the lock which fits right into the coupler of your trailer. It comes with a No. 50 padlock which you can lock on the spot.

Frequently Asked Questions (FAQ)

What is the best trailer coupler lock?

Since RVs come equipped with locking couplers, you can use the same lock to keep the trailer from being stolen. The lock comes with 3 keys. To lock the coupler, put the lock on and take the jackknife-style key and insert it into the keyhole. The keyhole is about the size of a quarter. Insert the key in the keyhole at a 45-degree angle. While holding the lock steady with one hand, turn the key with the other hand. Continue to give it a half turn until the lock is tight.

How do I protect my trailer from being stolen?

It’s a bad idea to park a trailer on the roadside even for a brief moment. Thieves will use the open back of your trailer as an easy access point to steal from it. This is why a trailer coupling lock is a must-have in every trailer owner’s inventory.

Your options aren’t limited though as there are many to choose from. I took the time to research and try a few in order to find out which ones really work. I ranked them in this guide so you can easily decide which one to get.

It’s important that the lock you get is safe for your trailer as some may be too heavy for it and cause it to tip over. The stronger the lock you get, the better (unless of course you’re into all that hot-wiring stuff).

How do you secure a trailer coupler?

There’s a variety of locks for trailer couplers such as the D-shaped lock, the bolt-on lock, the plug lock and the chain lock. When it comes to securing your trailer coupler from theft, the D-shaped lock is a highly effective option because of its unique design. It provides a permanent lockdown which will not let go no matter how much pressure is applied.

The disadvantage of this lock design, however, is that it takes a long time to detach. In critical situations, you could use a bolt-on lock which is also tough but faster than the D-shaped lock. The disadvantage is that it is not permanent and can be removed with tools. A plug lock and a chain lock are both permanent and durable but the most difficult to install. They are also a little expensive.

Who makes the best trailer hitch?

In my experience, the best trailer hitch is Reese. It is one of the most reliable one when I pull my travel trailer and it fits both 2 and 1-1/4 receivers.


If you’re frequently traveling with a trailer, then you need a product that will help you secure it from a thief. When choosing the best trailer coupler lock, don’t compromise on quality or ease of use. It’s a well-spent investment that will help you sleep easier at night.

Our Recommendation

Master LockBest OverallMaster Lock
Master Lock 377KA Trailer Hitch LockBudget PickMaster Lock 377KA Trailer Hitch Lock
Trimax UMAX100 Premium Universal 'Solid Hardened Steel' Trailer LockUpgrade PickTrimax UMAX100 Premium Universal 'Solid Hardened Steel' Trailer Lock