Top 8 Best Trailer Locks
By | Last updated: March 10, 2021
best trailer locks

Yeah, it sucks these things exist. But it doesn’t matter what’s in the trailer— boxes of tools, camping equipment, or a Hemi ‘Cuda — it all makes a tempting target for the criminal element. This goes for camping trailers, too. A retailer near your author’s hometown has to deal with loss prevention more often than anyone would care to admit. After all, in most cases, the theft is as simple as a hitch-up-and-go.

In the same way The Club steering-wheel lock is used to simply provide a deterrent, rather than making your ride theft-proof, so do these hitch locks for trailers. For fun, go search up the Lockpicking Lawyer on YouTube. He’ll be referred to multiple times in this posts as LPL.

Still, if there are two units side by each, a thief will likely make off with the one that provides the least resistance to an easy payday. A person should still lock the doors on the thing or, if it’s a flat deck, find some other way to secure the valuables.

Meaning, of course, none of these are a total waste of money. Something is always better than nothing and we waded through a few different options so you don’t have to.

1. Editor’s Pick: Reese Towpower Universal Coupler Lock

This is the editor’s pick because it’s the one your author uses on his own trailer. No, it isn’t the most expensive on our list, and a determined thief can defeat the thing with two quick zips of an angle grinder or ramset. Talented lockpickers like LPL can also gain entry. It is, however, an effective deterrent and easy to use. Its universal fit is good for many different hitch sizes.

A c-clamp style locking mechanism slides down over the hitch’s top while a spherical insert goes plugged into the business end of your trailer’s tongue. Push to lock, no key required. It does come with a pair of keys to unlock the thing. Personal experience has taught your author the c-clamp will rub against the trailer hitch, scraping off paint and causing surface rust. It’s not critical but is unsightly.

Pros/Affordable, easy-to-use, aluminum body and steel bar
Cons/Could be easily defeated by a determined thief
Bottom Line/A great deterrent

2. Master Lock 377KA Trailer Hitch Lock

Based on a heady 2,100+ reviews, this thing from Master Lock is the clear popularity king in the school of trailer locks (trailer locks, hard knocks, … no? Fine.) This unit is chrome plated and only weighs a couple of pounds. Unlike the Reese lock, this one fits into the trailer tongue in a horizontal fashion, making for a less intrusive look and avoiding paint rub.

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It fits many different hitch sizes and allegedly will resist rust and corrosion when exposed to bad weather. Turning the key allows the shackle to slide toward the coupler, foiling casual thieves trying to make off with your tow behind. Our friend on YouTube severely dislikes Master Lock products but a 4.6 out of 5 star rating from buyers suggests this is ok for the average buyer.

Pros/Lightweight, horizontal installation
Cons/Chrome-like style may attract attention
Bottom Line/LPL would laugh heartily but the real-world reviews are positive

3. InSite Solutions Steel Ball and Ring Hitch Lock

Made of steel and weighing no more than a single pound, this lock might look bulky but it’s found plenty of fans on Amazon garnering a 4.5 out of 5-star rating based on a decent sample size. The seller promotes this lock for use on equipment trailers – y’know, the type carrying zillion-dollar construction gear.

One reviewer claims to have defeated the lock itself with a shim (must’ve been watching LPL videos) while another said they had issues turning the cylinder in cold weather. Others describe it as ‘a beast’ and praise the manufacturer’s decision to use 3/8″ plate steel instead of light casting metal.

Pros/Fits several different hitch sizes
Cons/Expensive
Bottom Line/Weird looks but seemingly good protection

4. Trimax UMAX100 Trailer Lock

Anything with “solid hardened steel” in its title description earns this gearhead’s notice. One size should fit most couplers and, unlike others here, there is a cover for the keyhole to keep out debris and other nonsense that can scupper the lock’s use.

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It is of the same design as your author’s Reese unit, which is to say it deploys a twin ratchet system that passes vertically through two parts of the lock. The body of the thing is painted an appropriate black, while the ratchet loop portion that swings over top of the coupling is chrome color. This means it’ll likely wear off some of the hitch’s paint over time. Keep a spray bomb handy.

Pros/Cheap insurance, stealthy appearance
Cons/Certainly not the cheapest one here
Bottom Line/Covered keyhole helps in foul weather

5. AMPLOCK Trailer Lock - 2" coupler only

This 5-pound brute isn’t cheap but reviews seem to indicate that it may be worth the cash. Unlike others in this list, it has a center bolt-type feature that goes up where the hitching ball normally goes, while the rest of it grabs the coupler lip. Some customers reported frustration in mounting the thing (mind, gutter, etc) but other respondents were quick to jump in the comments and offer practical advice. Who knew there was a community for trailer locks?

This lock is good for a 2-inch only, meaning it’ll fit common couplers like those on campers but small utility trailers might be out of luck. This means you’ll need to order the specific size for your trailer, so be sure you’ve selected the right one before hammering that ‘buy’ button.

Pros/Snug fit, not painted bright yellow
Cons/Costs well over a hundred bucks
Bottom Line/Make sure you get the correct size

6. Master Lock 389DAT Universal Coupler Lock

You guys and girls know that I’m a sucker for anything painted a bright color, even when it shouldn’t be. Trailer definitely fall into that category, as logic dictates it’s definitely better not to advertise the fact you’ve got a trailer worth stealing. The inclusion of another Master Lock in our list will surely raise LPL’s blood pressure. But this is my post and I’m including it.

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The business end of this lock goes pushed into the trailer’s coupler at which time the bid (red) shield is ratcheted forward to engage the whole works. It is a featherweight two pounds and is reasonably priced. Nearly 95 percent of customers gave it a four or five-star review, a development our LPL friend will surely find outrageous.

Pros/Good price, great reviews, it’s red
Cons/Ratchet style engagement, it’s red
Bottom Line/It's red

7. Tow Ready Gorilla Guard Coupler

Gorilla Tape is pretty good, but what about Gorilla Guard? The tape doesn’t matter, as it may share a name but is not made by the same company. What we can tell you is that this lock is built to protect a 2-inch ball, meaning it won’t have the wobble and shake of some universal units. Its design means it won’t fit all couplings, however, with the widest it’ll accept being a width of 3-13/16 inches and a height of 5/16 of an inch. It would not fit my trailer, for example.

For those of whom it will, this is not a bad option. Made of heavy duty material, this lock slides horizontally onto a trailer ball to scupper unauthorized hitching of an unattended trailer. One customer reports they were forced to leave their boat trailer on the street overnight. Upon inspection, it was revealed someone tried to hammer off the lock but was unsuccessful in doing so. That’s a pretty reassuring anecdote.

Pros/Tough enough to stand up to a hammer attack, slim design
Cons/That slim design means it won’t fit all trailers
Bottom Line/Good for 2-inch couplers only

8. CURT Powder-Coated Aluminum Trailer Tongue Lock

Powder coating usually shows up on exhaust parts and chassis frames, not trailer locks. Nevertheless, here it is, blasted onto a uniquely shaped lock made of aluminium sold by a recognized brand name that sells a ton of other trailer gear. This lock is good for 2- and 2 5/16- inch couplers, so it won’t shake loose on the common two-incher.

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Sliding horizontally onto the trailer tongue, this lock prevents thieves from backing their tow vehicle up to your trailer’s hitching point and making off like a buncha bandits. By blocking off the portion of the tongue into which the truck’s hitch ball is placed (yay for double entendres!), it provides a good deterrent against the night shift looking for a five-finger discount.

Pros/You’ll be the only one at the campground with a powder coated lock
Cons/A surprising amount of bling
Bottom Line/Ensure fit before ordering

Notes on Trailer Locks and Trailering in General: It’s always good advice to park an unattended trailer in a well-lit area or in a locked place where the thing can be checked on frequently. No anti-theft device is perfect, of course, and all the manufacturers on this list have plenty of fine print about not being ultimately responsible for the loss of your toys.

Trailer Lock FAQs

Are these a waste of money?

We don’t think so. Very few locks in this world – including those on this list – are completely resistant to determined or skilled thieves. As LPL plainly shows on his YouTube channel, many of the very items on this list can be defeated.

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Then they are a waste of money!

No, they aren’t. If there are five trailers on a lot and yours is the only one with a lock, there is an excellent chance the robber will nab the one that’s easiest to take – and that won’t be the one with a lock on it.

OK, fine – any other advice?

Just make sure you’re buying a lock that fits the coupler on your trailer. Incorrect sizing can render even the best lock totally useless. Buy one with which you’re comfortable and can easily install when parking your trailer.

One last bit of advice

When you park your trailer, chocking the wheels is another excellent idea to avoid unexpected calamity. If it has brakes, after all, they’re only activated by the truck and not on their own. A runaway trailer is no fun. Some owners take it to the extreme and affix a parking enforcement boot to one of the trailer wheels but that just makes it look like it lives in the city of Chicago (Ed. note — hey! (and yes, you can buy parking boots on Amazon)). That’s probably the best takeaway out of all this, in fact.

Stay alert, stay safe!


From time to time, TTAC will highlight automotive products we think may be of interest to our community. Plus, posts like this help to keep the lights on around here. Learn more about how this works.

(Editor’s note: This post is meant to both help you be an informed shopper for automotive products but also to pay for our ‘90s sedan shopping habits operating expenses. Some of you don’t find these posts fun, but they help pay for Junkyard Finds, Rare Rides, Piston Slaps, and whatever else. Thanks for reading.)

[Main photo credit: Nattapon B / ShutterStock.com. Product images provided by the manufacturer.]

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