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The short version: a hitch lock is cheap insurance against having your ball mount, cargo carrier or entire trailer walk off — and there are two theft points to think about. A receiver lock secures whatever is in your hitch; a coupler lock secures a parked, unhitched trailer. Our #1 pick, the CURT 23086 set, covers both with one key. The Master Lock 2848DAT is the value receiver lock, and the Trimax TS32 is the high-security upgrade. The one spec you must get right is pin size — 1/2 inch for small receivers, 5/8 inch for most trucks and SUVs. Below is the full ranked field and how to choose.
A lock is one part of securing your trailer — pair it with correctly rated ST trailer tires, a solid trailer jack, and working trailer lights. See the full roadside emergency & safety hub for the rest of the towing kit.
Top Picks at a Glance
Our #1 Pick: The CURT 23086 Lock Set
The CURT 23086 tops the list because it secures both places a thief goes after in one keyed-alike set. The receiver lock replaces the hitch pin so no one can slide out your ball mount, bike rack or cargo tray, and the coupler lock blocks the trailer latch so a parked trailer cannot be dropped onto a ball and towed off. One key operates both, which owners appreciate over juggling separate locks. It fits standard 2-inch receivers with a 5/8-inch pin — the most common setup on trucks and SUVs — so confirm your receiver class and coupler size, and you have both theft points covered.
Best for locking both the hitch pin and the coupler with one key
- Receiver hitch lock + coupler lock
- Fits 2-inch receivers, 5/8-inch pin
- Keyed alike — one key for both
- Covers both common theft points
Why buy it: the most complete pick — it locks the ball mount into the receiver and locks the coupler onto the ball, both keyed alike, so one key secures the two places a thief would attack.
Best for a cheap, well-made receiver pin lock
- Fits both 1/2-inch and 5/8-inch holes
- Push-to-lock, key removes to lock
- Chrome-plated, weather-resistant
- Locks a ball mount or cargo carrier
Why buy it: the value receiver lock — includes both pin sizes so it fits Class I–IV receivers, and the push-to-lock design means you just push it on and pull the key, praised by owners for years of use.
Best for a high-security, drill-resistant receiver lock
- Type-A 7-pin, drill-resistant key
- Fits 5/8-inch receiver hole
- Lifetime guarantee
- Extra-strong bend-resistant pin
Why buy it: the security upgrade — a 7-pin drill-resistant cylinder and a heavy pin that will not bend, backed by a lifetime guarantee, for owners who want more than a basic lock on the receiver.
Best for rust-free security in wet or coastal use
- Stainless steel, corrosion-resistant
- 5/8-inch pin for Class III–IV
- DogBone style, easy to handle
- Weather-sealed cylinder
Why buy it: the rust-proof pick — stainless construction that shrugs off rain, road salt and coastal air, which owners who leave a lock on year-round or tow near the ocean specifically look for.
Best for stopping theft of a parked, unhitched trailer
- Fits 1-7/8, 2 and most 2-5/16 couplers
- Blocks the coupler so it cannot hitch
- Weather-resistant body
- For a trailer stored off the vehicle
Why buy it: the parked-trailer defender — it fills the coupler so no one can drop it onto a ball and tow it away, the lock you want on a boat or utility trailer sitting in the driveway.
Best for heavy-duty 2-inch and 2-1/2-inch receivers
- Fits 2-inch and 2-1/2-inch receivers
- 5/8-inch pin, 3-1/2-inch span
- Rugged pewter finish
- For heavy tow rigs and big carriers
Why buy it: the big-rig pick — a longer-span Class 5 lock that fits the larger 2-1/2-inch receivers on heavy tow trucks and beefy cargo carriers where a standard lock is too short.
Get the Pin Size Right — 1/2 or 5/8 Inch
This is the fitment detail that trips people up. Smaller Class I and II receivers use a 1/2-inch pin hole, while Class III, IV and V receivers — most trucks and SUVs — use a 5/8-inch hole. Measure the hole or check your receiver’s class before you order. If you are not sure, a lock like the Master Lock 2848DAT that includes both sizes or a sleeve is the safe bet. A pin that is too small rattles in the hole and secures nothing well, and a pin that is too large simply will not fit, so match the lock to your receiver.
Two Theft Points: Receiver and Coupler
Securing a trailer setup means thinking about two separate weak points. The receiver is where your ball mount, bike rack or cargo carrier slides in — a receiver (hitch pin) lock replaces the pin so that gear cannot be pulled out. The coupler is the trailer’s hitch cup — when the trailer is parked and unhitched, a coupler lock fills or blocks it so no one can back a ball under it and tow it away. If you leave a ball mount or carrier in your truck, you want a receiver lock; if a trailer sits in your driveway, you want a coupler lock; if both, buy a set. This is why we rank a combination set at the top.
Security Is a Deterrent, Not a Guarantee
Be realistic about what a lock does: it raises the time and effort a thief must spend, which sends them looking for an easier target rather than making theft impossible. That is exactly why the extra security features matter if you leave gear out. A drill-resistant cylinder (Trimax TS32) resists picking and drilling, and a hardened or stainless body resists cutting and rust. Pair a good lock with common sense — park in view, do not leave a valuable ball mount or bike rack out overnight, and lock both points on a parked trailer — and you have covered the realistic threats.
Locking Hitch Pins vs Standard Pins
A plain hitch pin holds your ball mount in but does nothing to stop theft — anyone can pull the clip and slide the whole thing out. A locking hitch pin swaps that clip for a keyed cylinder, so the pin cannot be removed without your key. If you leave a ball mount, bike rack or cargo carrier in the receiver, upgrading a standard pin to a locking one is the single cheapest security win. Standard pins are fine only when nothing of value stays in the hitch between trips.
Heavy-Duty Locks for Towing Trailers
For serious towing, step up to a heavy-duty lock built for the load and the target. Big trailers, boats and enclosed cargo trailers are high-value theft targets, so a hardened coupler lock plus a receiver lock is worth it. Brands like TowSmart make heavy-duty locks sized for Class IV and V receivers and larger couplers. One robust lock at each point deters the grab-and-go thief who cruises for an easy trailer. Match the lock’s rating to the trailer you are securing.
Build Quality and Brands to Trust
The lock’s build decides whether it survives years outdoors and resists attack. USA-made hardened steel and stainless bodies hold up best; look for a seller or brand with a long track record — CURT, Master Lock, Trimax, Reese, TowSmart, and value names like Beech Lane. Owners consistently recommend buying from a reputable seller rather than the cheapest listing, and the highest recommendation goes to locks people actually bought and left on for years without a seizure. Quality here is measured in seasons survived, not the price on the box.
How We Rank
A hitch lock earns trust by resisting attack and surviving the weather without seizing, so we rank by aggregated owner ratings, review volume and the themes owners repeat rather than a lab break-in test. We weigh four things. Security — cylinder quality, drill and pick resistance, and how hard the lock is to defeat. Weather resistance — stainless or sealed construction that resists rust and freezing outdoors. Fitment — coverage of the common pin sizes and receiver classes, stated plainly. And value — protection against price, including sets that cover both theft points. We are clear about which locks secure the receiver, the coupler, or both. Prices were current at the time of writing.
Quick Comparison
CURT 23086 Trailer Lock Set (Receiver + Coupler)
Best for locking both the hitch pin and the coupler with one key
Best Value
Master Lock 2848DAT Receiver Lock (1/2 in. & 5/8 in.)
Check Price on Amazon
Best Premium
Trimax TS32 Deluxe Receiver Lock
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Best Weatherproof
Reese Towpower 7030200 Stainless DogBone Receiver Lock
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Best Coupler Lock
Master Lock 377KA Trailer Coupler Lock
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Best for Large Receivers
Reese Tactical 7092330 Class 5 Receiver Lock
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The Verdict
For complete coverage, the CURT 23086 set locks both the receiver and the coupler with one key — the pick owners rate highest for securing the whole setup. Only need a receiver lock? The Master Lock 2848DAT is the value choice with both pin sizes, and the Trimax TS32 adds drill-resistant security. Whatever you choose, match the pin size to your receiver class. Check Price on Amazon →