Last updated: 16/10/2022

Welcome to our large trailer lock test 2023. Here we present all the trailer locks we have tested in detail. We have compiled detailed background information for you and also added a summary of customer reviews on the Internet.

We would like to make your purchase decision easier and help you find the best trailer lock for you.

You will also find answers to frequently asked questions in our guide. If available, we also offer interesting test videos. Furthermore, you will also find some important information on this page that you should definitely pay attention to if you want to buy a trailer lock.


  • Trailer locks are an essential measure against trailer theft and can be found in three different variants.
  • A basic distinction is made between trailer locks with low, medium and high protection against theft.
  • Although there are other variants for theft protection, trailer locks are the most common method of protecting against thieves.

The Best Trailer Lock in the United Kingdom: Our Choices

Guide: Questions you should ask yourself before buying a trailer lock

What is a trailer lock?

A trailer lock is a special lock that typically protects trailers and caravans from being operated by unauthorised persons.


To avoid losing a trailer, many people who own a trailer turn to more reliable means of protecting their investment. (Image source: / stevepb)

Vehicle trailers, after purchase, in most cases have a simple mortise lock. The purpose of this lock is to protect the trailer from theft.

There is a possibility that mortise locks can be picked in no time by amateurs. Basically, you can call a trailer lock a reliable anti-theft device.

How does a trailer lock protect against theft?

In principle, the function of all locks is the same. The lock has the task of protecting the object from unauthorised persons.

Since a trailer, due to its size, cannot easily be moved from one place to another and normally requires a car to do so, a lock is used to break the connection between the trailer and the car.

The purpose of the lock is that you can no longer couple a vehicle to the trailer without removing the lock in front of it.

An ordinary mortise lock and the trailer’s integrated lock system can be picked relatively easily and with little experience. This requires simple bolt cutters, which are very likely to be used by any trailer thief.

However, there is another function that a trailer lock has to protect against theft. The lock has the property of serving as a deterrent.

Casual thieves therefore prefer to look for simpler goods that can be stolen with less effort.

What does a trailer lock cost?

There are relatively large price differences between the various trailer locks. The general differences in terms of price depend mainly on the category of the trailer lock.

This means that the effectiveness in protecting against theft plays a major role in the price. Therefore, a certified, high-ranking trailer lock can sometimes cost 120 euros, whereas simpler lock variants are available for as little as 5 euros.

However, the price is strongly dependent on the manufacturer and is usually influenced by the manufacturing material. For example, solid box locks with hardened steel are much more expensive than simpler locks, but they also offer a higher protection factor.

variant price range
low theft protection 5 – 10€
medium theft protection 15 – 25€
high theft protection 80 – 130€

What alternatives are there to a trailer lock?

Of course there are alternatives to protect your trailer from theft. These alternatives are also much more effective in combination with the trailer lock in the fight against trailer theft.

Alternative Function
Tyre claw Makes turning of the trailer wheel impossible
Secure parking locations A video-monitored parking area also provides theft protection

Ultimately, it is up to you how and to what extent you want to protect your trailer lock. However, depending on the product, all the alternatives have certain advantages and disadvantages that you should consider.

A trailer lock is a special lock that typically protects trailers and caravans from being operated by unauthorised persons. (Image source: / Isaac Moore)

Trailer locks are nevertheless the most commonly used means of protection against theft.

Decision: What types of trailer locks are there and which is the right one for you?

If you want to buy a trailer lock, you have the choice between three types:

  • Simple trailer locks
  • Medium security trailer locks
  • Certified trailer locks

The simple trailer lock s are plug-in locks that are usually included with the purchase of a trailer.

The medium-security trailer locks basically include the box locks, which are a very popular purchase among trailer owners because of their good price-performance ratio.

Certified trailer lock s are the last variant and are often only manufactured individually. Depending on how you want to use your trailer lock, a different type is suitable.

In the following section we want to help you make your decision.

What are the advantages and disadvantages of a simple plug-in lock?

A simple plug-in lock is, as the name suggests, pushed (inserted) into a locking channel of the trailer coupling and then locked with a corresponding key.

The advantage of the plug-in lock is that it is very easy to use. It is also very easy to stow away. With the size of a key, it is very easy to stow away in the glove compartment.

  • Easy to use
  • Easy to store
  • Inexpensive
  • Easy to crack
  • Easily unmissable and therefore no high deterrent effect

What distinguishes a rim lock and what are its advantages and disadvantages?

Box locks have a very distinctive appearance. Due to the box-like construction of the lock, they not only protect the entire coupling of the trailer, but also have a high ability to deter thieves.

However, with a length of 23 cm and a width of 12 cm, the steel box is difficult to store in the vehicle due to its size and can cause inconvenience when driving.

  • Good value for money
  • Protects against damage
  • High deterrent effect
  • Unhandy
  • Difficult to fit

Another disadvantage is that a box lock is difficult to handle. Because the housing is relatively massive, installation does not always come off with ease. For campers and trailer owners who are definitely in a hurry, this can be their undoing.

An advantage is the stability of the hardened steel housing. This makes the lock much harder to pick than a simple mortise lock and it cannot be removed with a simple hammer, for example.

In addition, the lock protects against slight bending that could be caused, for example, by a vehicle driven on the other side.

What distinguishes a certified trailer lock and what are its advantages and disadvantages?

Since certified trailer locks are created individually by certain manufacturers, they usually have different appearances.

However, all of them are characterised by the quality of the production and the material. Whereas simpler locks are usually made of cast iron or brass, the certified trailer locks are completely different.

  • Mounted while driving
  • High security
  • High deterrent
  • High cost
  • Hard to find locally (DE)

These are often made of stable and qualitative materials. Individual shapes and components also ensure high security standards for certified trailer locks.

Some products even use eye-catching colours that have the purpose of catching thieves’ eyes even more easily. There are also some variants that allow the lock to be left attached to the hitch while driving.

The disadvantage of certified trailer locks is that they are not so easy to find in Germany. In most cases, this category of locks can only be found in online shops.

Buying criteria: You can use these factors to compare and evaluate trailer locks

In the following, we will show you which aspects you can use to decide between the many possible trailer locks.

The criteria with which you can compare the anti-theft device for trailers include:

  • Material
  • Size
  • Mounting
  • Security class

In the following paragraphs we will explain to you what is important in the individual criteria.


This criterion is very important when choosing a trailer lock, as it directly contributes to the security and protection of the trailer.

In any case, you should be aware that simple socket locks are usually made of cast iron. Cast iron is relatively unstable and can be easily broken.

Therefore, look for a lock with a harder metal, such as brass.

It is also very important to check the keys of the lock before buying. If they look too small or fragile, you should be aware that these keys could break very easily.

In the worst case, you would have to break the lock with tools or a drill.

Box locks are generally made of hardened steel. Check with your manufacturer that it is indeed hardened steel and not a fragile substitute.

It is very important to look at the quality of the weld on box locks. If you find any irregularities, it can cause the lock to break very easily.

The lock is only as strong as the materials used to make it. It is best to watch this video to identify faulty welds:

Since certified trailer locks are only made with selected high quality materials, you do not need to worry about the material.

Nevertheless, the product should be checked for quality. The price should also correspond to the quality.


Since there are different types of trailer locks, there will also be different sizes of locks.

First of all, you should be aware of which variant of the lock suits you best.

Padlocks generally have a length of 15 cm to 20 cm and a width of about 12 cm. Since most manufacturers build an integrated socket lock into their trailers, the size of the lock in this case is similar everywhere. Nevertheless, check the compatibility with your trailer.

For box locks, however, the size may vary depending on the manufacturer. Basically, the length, width and height of the lock are 210 mm, 108 mm and 127 mm respectively.

However, it is very important that you measure the length, width and height of your trailer coupling before buying and then come to a decision.

In some cases, the certified trailer locks are similar to the box lock. However, there are manufacturers who make customised locks. Often the size then corresponds with the individual design of the manufacturer.


Simple socket locks are installed simply by inserting the socket lock into the slot provided in the trailer hitch.

This video shows how this is done:

For box locks, the installation may vary depending on the type. However, the box locks are always mounted in a very similar way.

First, the box is slipped over the coupling of the trailer. Then a security bolt with a so-called discus lock is locked through a slot on the side.

To get a better picture of this, it is worth watching this video:

Security class

Basically, you can distinguish between three different types of security class. Trailer locks with:

  • low theft protection
  • medium theft protection
  • high theft protection

Locks with low protection

These locks include simple mortise locks. These locks are installed by the trailer manufacturer in most cases, but can still be retrofitted by the owner if not available.

In addition, the simple mortise locks are cheap and easy to use, which can lead to problems.

The problem in this case is that locks of this form are easy to pick by levering them out and therefore offer only low protection against theft. They are therefore only effective as a deterrent against opportunistic thieves.

Locks with medium protection

So-called box locks are currently the most commonly used trailer lock variant.

With their sturdy and box-like appearance, these not only deter casual thieves, but are also much harder to pick than simpler locks.

The material is made of hardened steel and therefore ensures high stability and theft resistance.

Basically, larger tools are needed to pick a rim lock and therefore cannot simply be broken with a hammer blow or bolt cutters.

Locks with high protection

The most reliable and, to a certain extent, most expensive variant are certified trailer locks. However, these are produced and marketed by appropriately well-known manufacturers through individual construction.

Well-known manufacturers in the industry, such as “Alko Safety” and “DoubleLock”, ensure the highest level of security for trailer locks with high quality materials.

however, you should note that the availability of these certified trailer locks is only in countries where insurance companies require trailer locks of this class.

As there are no security criteria defined for theft protection in Germany, it could be advantageous for interested parties to import.

Facts worth knowing about trailer locks

What do I do with the trailer lock while driving?

Stowing a trailer lock can often become a problem. However, the size is often the problem here.

Whereas simple plug-in locks fit easily into a trouser pocket, it can quickly become a problem to find an ideal place to stow box or certified locks.

Many certified trailer locks have the ability to stay attached to the hitch of the trailer. Often these also provide further protection for the hitch when driving.

Box locks, however, do not have this capability and must be disassembled and securely stowed each time.

How do I recognise a certified trailer lock?

Certified trailer locks are only made by certain manufacturers. The distinctive quality and the associated price often speak for the certification.

In most cases, the manufacturer is specialised in the field of anti-theft and trailer protection. It is helpful to read reviews about the product and look for the word “certified”.

Image source: / Blake Wisz