Best Trailer Lock For Bulldog Hitch: 10 Options Compared

#1 · Best Overall

1. Collar Marketing Bulldog Lock

• Weight: 1.46 lb

Best for: Attached-trailer Bulldog protection.

Why it ranks #1: Works with all listed Bulldog and Ram latch styles and can secure the trailer while attached to a vehicle or detached.

Protection while the trailer is attached to a vehicle is the Collar lock’s defining use, addressing a situation its listing says many locks do not cover. Its stainless-steel body works with Bulldog and Ram latch styles, giving owners a specific coupler-lock option for both connected and detached parking.

The Collar lock is expressly described for security whether the trailer is attached to a vehicle or detached, supporting use across connected parking and standalone storage. Its heavy-duty stainless-steel body is said to resist cutting, grinding, and the elements, linking material choice to the listed threats and outdoor exposure. Compatibility covers all Bulldog and Ram latch styles, with example couplers shown in the product pictures. At 1.46 pounds, it is lighter than several heavy steel lock bodies listed here.

Skip it if you need a lock for a 2-inch Bulldog size-based fit; Proven Industries 2178-B lists select 2-inch Ram or Bulldog couplers.

This is a match for Bulldog or Ram owners who want protection with the trailer either hitched or detached. Its stated compatibility centers on those latch styles, so other coupler families fall outside the listed fit.

Listed on Amazon as: The Collar Trailer Hitch Lock for Bulldog-Style Couplers (Including The RAM)

#2 · Best Sliding-Collar Fit

2. Ft. Knox Bulldog Sliding Collar Lock

• Weight: 8 lb
• Material: Steel

Best for: Bulldog sliding-collar specialists.

Why it ranks #2: Designed specifically for Bulldog sliding-collar couplers and includes a Trimax puck lock with three keys.

A precise fit for Bulldog sliding-collar couplers is the defining feature of this Ft. Knox lock, which includes a Trimax puck lock. Welded industrial-grade steel and the supplied puck lock form a full-enclosure approach for owners securing compatible trailers during storage, parking, or transport.

The product is explicitly limited to Bulldog sliding-collar couplers, so its specialized fit is useful only when the trailer has that style. Heavy-duty welded steel is described as resisting bolt cutters and crowbars, connecting its construction to common forced-entry tools. The included Trimax puck lock and three keys complete the stated enclosure, giving owners the lock and keys in the package. Its listed use cases include contractors, haulers, RV owners, and utility trailers during parking or storage.

Skip it if you have a non-sliding-collar Bulldog coupler; Proven Industries Model 2517-B1 lists select dome-top Bulldog couplers instead.

This is for owners whose Bulldog coupler uses a sliding collar and who want the included Trimax puck lock as part of the enclosure. It is not a general Bulldog fit, making coupler style the key boundary.

Listed on Amazon as: Ft. Knox Locks Bulldog Sliding Collar Trailer Coupler Lock with Trimax Puck Lock – Bolt Cutter & Crowbar Proof, Made in USA

#3 · Best Dome-Top Fit

3. Proven Industries 2517-B1

• Dimensions: 9 x 8 x 6 in
• Weight: 15 lb
• Material: Alloy Steel

Best for: Square and dome-top Bulldog fit.

Why it ranks #3: Fits select square and dome-top Bulldog couplers and includes a lock body, puck lock, and keys.

Compatibility with select square and dome-top Bulldog couplers distinguishes the Proven Industries Model 2517-B1 from locks aimed at standard size ranges. Its hardened-steel locking parts and protective exterior cover give owners of those specific coupler shapes a purpose-matched security assembly with a puck lock and keys included.

The product is listed for select dome-top Bulldog couplers, and its title identifies square and dome-top Bulldog couplers, so it targets particular shapes rather than universal use. Hardened-steel locking parts provide the internal locking element, while a tough exterior cover is described as shielding against power tools, hammers, and crowbars. The included components are the lock body, puck lock, and keys, providing the core assembly needed to secure a compatible coupler without choosing a separate puck lock.

Skip it if you need a 2-inch Ram coupler lock; Proven Industries 2178-B lists select 2-inch Ram or Bulldog couplers.

Choose this if your trailer has a compatible square or dome-top Bulldog coupler and you want a lock body with puck lock included. Its fit is limited to select shapes, so confirm the coupler matches the listed configuration.

Listed on Amazon as: Proven Industries Model 2517-B1 Trailer Lock, Fits Square and Dome-Top Bulldog Couplers, Made in the USA, (Black)

#4 · Best Two-Size Coverage

4. VEVOR Bulldog Trailer Lock

• Dimensions: 8.86 x 4.53 x 4.53 in
• Weight: 11.9 lb
• Material: Carbon Steel

Best for: Two-size Bulldog coupler coverage.

Why it ranks #4: Fits 2-inch and 2-5/16-inch Bulldog couplers, weighs 11.9 pounds, and includes three keys.

Compatibility with both 2-inch and 2-5/16-inch Bulldog couplers is this VEVOR lock’s defining feature, giving owners of either listed size one security option. Its 11.9-pound carbon-steel body adds substantial mass, while the coated surface supports corrosion resistance for trailer use in varied weather.

The two specified coupler sizes make this a candidate for owners whose Bulldog coupler measures 2 or 2-5/16 inches; checking the coupler against the listing images helps avoid a mismatch. A 0.24-inch-thick carbon-steel wall and 11.9-pound weight give the body a substantial construction, while the coating is identified as corrosion resistant. The listed package includes one coupler lock, and the title specifies three keys, a practical detail for keeping spares available.

Skip it if you have a Bulldog coupler outside the two listed sizes; the Master Lock 379ATPY lists three coupler sizes instead.

Choose it if your Bulldog coupler is 2 or 2-5/16 inches and you want a substantial steel lock with a corrosion-resistant coating. Its fit is limited to those two listed sizes, so coupler measurement matters.

Listed on Amazon as: VEVOR Trailer Lock, Fits 2 & 2-5/16-Inch Bulldog Trailer Couplers, Heavy Duty Hitch Lock with 3 Keys Secures Security Chains, Corrision-Resistant, Anti-Theft RV Trailer Locks for RV, Trailer, Boat

#5 · Best Adjustable Fit

5. AUREOASIS Universal Trailer Lock

• Dimensions: 6.49 x 6.29 x 7.67 in
• Weight: 10.1 lb
• Material: Steel

Best for: Adjustable multi-style coupler fit.

Why it ranks #5: Its adjustable mechanism is listed for 2-inch, 2-5/16-inch, and Bulldog couplers, with a 10.1-pound steel body.

An adjustable locking mechanism is the key feature of this AUREOASIS lock, supporting fit across most 2-inch and 2-5/16-inch couplers as well as Bulldog couplers. Its heavy hardened-steel construction and included spare keys make it a flexible option for owners managing more than one compatible trailer setup.

The adjustable mechanism is described as fitting most 2-inch and 2-5/16-inch couplers and Bulldog couplers, offering broader listed coverage than a lock tied to one coupler size. An internal adjustable slider hugs the ball joint to minimize movement, connecting the fit mechanism with a close-seating installation. The product includes spare keys, useful for keeping an extra on hand, and setup video information covers A-frame, straight, and Demco installations. The listing still recommends verifying fit.

Skip it if you need a lock explicitly limited to a particular Bulldog geometry; Proven Industries Model 2517-B1 specifies select dome-top Bulldog couplers.

Consider it if you want an adjustable lock spanning listed 2-inch, 2-5/16-inch, and Bulldog applications, with spare keys included. Because fit is stated as covering most couplers, the exact model still needs checking.

Listed on Amazon as: New-Universal Trailer Lock for 2-5/16",2" & Bulldog Couplers

#6

6. FixOasis Universal Trailer Lock

• Weight: 4.58 kg

Best for: Adjustable three-style compatibility.

Why it ranks #6: The adjustable lock is listed for 2-inch, 2-5/16-inch, and Bulldog couplers; the listing describes steel and aluminum-alloy options.

Adjustable fit across 2-inch, 2-5/16-inch, and Bulldog couplers gives the FixOasis lock its broadest practical appeal. Buyers can also choose between puck-lock material options: silver versions use steel, while red or black versions use aluminum alloy, letting selection account for construction preference and visibility.

The adjustable design is listed for 2-inch, 2-5/16-inch, and Bulldog couplers, so it can accommodate several common configurations when the specific coupler is compatible. FixOasis distinguishes its silver puck-lock option, made of steel for stronger anti-drilling and anti-cutting capability, from red or black aluminum-alloy options that provide bright visual deterrence. Installation guidance for different couplers is available in the product video. The material and color choice therefore affects the type of protection emphasized.

Skip it if you want steel for the puck lock regardless of color; Proven Industries 2178-B lists hardened-steel locking parts and an exterior shield.

This fits buyers comparing adjustable coupler coverage and puck-lock material or visibility options. Pick silver for the listed steel construction or red or black for bright alloy; verify the precise coupler is compatible before installation.

Listed on Amazon as: Universal Trailer Lock for 2-5/16", 2" & Bulldog Couplers

#7

7. Proven Industries 2178-B

• Dimensions: 7.26 x 5.13 x 8.36 in
• Material: Alloy Steel

Best for: Select 2-inch Bulldog or Ram fit.

Why it ranks #7: Fits select 2-inch Ram or Bulldog couplers and combines hardened-steel locking parts with an exterior shield and puck lock.

A hardened-steel locking assembly paired with a protective exterior shield defines the Proven Industries 2178-B. It fits select 2-inch Ram or Bulldog couplers, making it a focused security option for owners who want a layered lock construction rather than broad, multi-size compatibility.

The fit is specific to select 2-inch Ram or Bulldog couplers, so matching the coupler to the listing is central to choosing this model. Hardened-steel locking parts provide the internal security component, while the tough exterior cover is described as protecting against power tools, hammers, and bolt cutters. The included components are an inner slide, exterior shield, and puck lock, creating a multi-part assembly that surrounds the coupler rather than relying on a bare lock alone.

Skip it if you have a square or dome-top Bulldog coupler needing that specific fit; Proven Industries Model 2517-B1 lists those coupler shapes.

Consider this for a select 2-inch Ram or Bulldog coupler when a shielded, multi-part lock assembly matches your needs. Its compatibility is specific, so owners with other sizes or coupler forms should use a lock listing them.

Listed on Amazon as: Proven Industries 2178-B Trailer Hitch Lock – Fits 2" Couplers, Black

#8

8. NiwNiw 2178-B

• Dimensions: 4.6 x 4.4 x 8.4 in
• Material: Carbon Steel

Best for: Bulldog and Ram puck-lock users.

Why it ranks #8: Fits 2-5/16-inch Bulldog or Ram couplers and uses a carbon-steel body with a push-button puck-lock design.

A push-button puck lock provides this NiwNiw trailer lock’s quick-securing workflow, while its stated compatibility covers 2-5/16-inch Bulldog or Ram couplers. The carbon-steel construction targets physical resistance, making it a focused option for owners of those specific couplers seeking a lock for trailer or RV security.

The push-button puck mechanism supports quick locking without a multi-step procedure described in the listing. NiwNiw identifies a hardened core and carbon-steel construction, connecting the lock’s materials to its stated resistance against attacks such as drilling and cutting. Its fit is specifically given as 2-5/16-inch Bulldog or Ram couplers, so owners should treat that size and coupler style as the boundary. The listed use cases include trailers, RVs, boats, trucks, and utility trailers.

Skip it if you need a lock for a 2-inch coupler; VEVOR Trailer Lock THS001 lists both 2-inch and 2-5/16-inch Bulldog fit.

This suits owners with a 2-5/16-inch Bulldog or Ram coupler who value push-button locking and a carbon-steel body. Its listed compatibility does not extend to other coupler sizes, so confirm the coupler type before choosing it.

Listed on Amazon as: 2178-B Heavy Duty Trailer Hitch Lock 2 Inch Bulldog or Ram Ball Coupler Anti-Theft,Travel RV/Camper/Boat/Truck/ATV/UTV/Flatbed/Cargo/Dump/Utility Trailer Tongue Lock Secure Design

#9

9. NUOVEPE 2178-B

• Material: Stainless Steel

Best for: One-click 2-5/16-inch Bulldog security.

Why it ranks #9: The listed fit is 2-5/16-inch Bulldog and Ram couplers; its disc-style lock is described as enabling one-click locking.

One-click locking is the defining convenience of the NUOVEPE 2178-B, which is listed for 2-5/16-inch Bulldog and Ram couplers. Its stainless-steel specification and disc-style puck lock combine a quick securing action with a focused fit, making it relevant to owners who park compatible trailers at campsites or work sites.

The patented disc-style puck lock and one-click secure feature support a straightforward locking workflow when securing a compatible trailer. The product description identifies a tight seal on 2-5/16-inch Bulldog and Ram couplers, so the stated fit is specific rather than universal. Stainless steel is named in the specifications, while the feature copy describes resistance to attacks including sledgehammers, power tools, crowbars, and freeze attacks. The listed applications include RVs, cargo haulers, utility trailers, and livestock haulers.

Skip it if you use a 2-inch Bulldog coupler; VEVOR Trailer Lock THS001 lists fit for 2-inch and 2-5/16-inch Bulldog couplers.

Choose this for a 2-5/16-inch Bulldog or Ram coupler when one-click puck locking suits your routine. Its specified fit is narrow, so owners with other sizes or coupler styles should select a lock listing those configurations.

Listed on Amazon as: 2178-B Blue Heavy-Duty Trailer Hitch Lock for 2 Inch Couplers

#10

10. Master Lock 379ATPY

• Dimensions: 3.6 x 7.6 x 6.7 in
• Weight: 16 oz
• Material: Alloy Steel

Best for: Visible multi-size coupler lock.

Why it ranks #10: Fits listed 1-7/8-inch, 2-inch, and 2-5/16-inch couplers, but the supplied fit information does not specifically confirm Bulldog compatibility.

A bright red finish makes this Master Lock easy to spot on a trailer, while its listed fit covers 1-7/8-inch, 2-inch, and 2-5/16-inch couplers. The advanced locking mechanism resists picking and prying, pairing visible deterrence with protection across three stated coupler sizes.

The three listed coupler sizes give owners of 1-7/8-inch, 2-inch, or 2-5/16-inch setups a single size-spanning option, subject to the specific coupler fitting. Its bright red finish is identified as a visible deterrent, making the lock easier to notice when checking a parked trailer. Master Lock also lists an advanced mechanism that resists picking and prying, alongside rust and corrosion resistance. Simple installation and removal support routine use without a complex setup described.

Skip it if you have a Bulldog sliding-collar coupler and want a dedicated collar lock; Ft. Knox Locks Bulldog Sliding Collar Lock targets that style.

This suits owners who want a readily visible lock and have a 1-7/8-inch, 2-inch, or 2-5/16-inch coupler. Its listed size range is the boundary, so other sizes or specialized coupler styles call for another option.

Listed on Amazon as: Master Lock Trailer Lock, Trailer Hitch Lock fits 1-7/8",2" & 2-5/16" Red