What you need to register a trailer in California

California requires you to register any trailer you tow on public roads, whether it is a utility trailer, boat trailer, horse trailer, or enclosed cargo trailer. The process is straightforward: you fill out an process, provide proof of ownership, pay a fee, and receive registration documents and a license plate. Unlike vehicle registration, trailer registration does not renew annually — you pay once and keep the same registration until you sell the trailer or it is no longer roadworthy.

The California Department of Motor Vehicles (DMV) handles all trailer registration. You can complete the process in person at a DMV office, by mail, or through an authorized third-party registration service. Most people find the mail route fastest if they have all documents ready, since DMV offices often have long wait times.

Key Takeaways

  • California trailer registration is permanent — you pay once and do not renew it annually like you do with a vehicle.
  • You will need the manufacturer's certificate of origin, a bill of sale, proof of ownership, and proof of California residency to register.
  • Registration fees depend on the trailer's dry weight and range from roughly $30 to $200, but exact amounts vary by weight class.
  • You can register by mail using Form REG 343, in person at a DMV office, or through a private registration service that charges an additional fee.
  • Once registered, your trailer receives a permanent license plate that stays with it for its entire life unless you transfer or surrender the registration.

Documents you need before you start

Gather these documents before you go to the DMV or prepare your mail process. If you are missing any of them, the DMV will reject your process and you will have to resubmit.

Proof of ownership is the foundation. If the trailer is new, you need the manufacturer's certificate of origin (also called an MCO). If you bought it used, you need a bill of sale signed by the previous owner, or a title document if the trailer was previously registered in California. The bill of sale should include the seller's name and signature, the purchase price, the date of sale, and a description of the trailer (year, make, model, VIN if available).

Proof of California residency is required for the registered owner. A California driver's license, state ID card, or utility bill with your name and current address works. If you do not have a California ID yet, a recent utility bill, lease agreement, or property tax bill dated within the last 60 days will do.

You will also need the Vehicle Identification Number (VIN) if the trailer has one. Older or very straightforward trailers may not have a VIN — if yours does not, note that on the process and the DMV will process it without one.

How to register by mail

Mail registration is often the fastest route because you avoid DMV office lines. read or request Form REG 343 (process for Permanent Trailer Registration) from the California DMV website or pick one up at any DMV office. Fill in your name, address, the trailer details (year, make, model, VIN, dry weight), and sign the form.

Include copies (not originals) of your proof of ownership and proof of residency. Write a check or money order for the registration fee — do not send cash. The fee is based on the trailer's dry weight. Trailers under 1,500 pounds cost around $30 to $40; trailers 1,500 to 3,000 pounds cost roughly $60 to $90; heavier trailers cost more. Check the DMV website for the exact fee table, as amounts can shift.

Mail everything to the address listed on Form REG 343 — it varies by county. Include a self-addressed stamped envelope if you want the DMV to return your documents. Processing takes two to four weeks by mail. You will receive your registration documents and a permanent license plate in the mail.

Registering in person at a DMV office

If you prefer to register in person, bring the original or certified copy of your proof of ownership, your proof of residency, and Form REG 343 completed and signed. Arrive early — DMV offices are busiest mid-morning and mid-week. Take a number and wait to be called.

The DMV representative will verify your documents, confirm the trailer details, and collect your fee. If everything is in order, you will walk out with your registration documents and permanent license plate the same day. If anything is missing or unclear, they will tell you what to fix and you can resubmit by mail or come back in person.

Some DMV offices allow you to make an appointment online through the California DMV website. Booking a time slot can cut your wait from an hour or more to 15 or 20 minutes, so check whether your local office offers appointments.

Using a private registration service

Private registration services (sometimes called DMV services or registration services) are authorized by California to handle registration paperwork on your behalf. You bring your documents to their office, they submit the process to the DMV, and you receive your registration and plate by mail. The DMV fee is the same, but the service charges an additional fee — typically $20 to $50 depending on the business.

This route is worth considering if you have a complex ownership situation (for example, a trailer owned by a business rather than an individual) or if the nearest DMV office is far away. Many registration services are located in shopping centers or strip malls and have longer hours than DMV offices. However, if your process is straightforward and you have all documents ready, registering by mail is usually cheaper and just as fast.

What happens after you register

Once the DMV processes your process, you receive a permanent registration card and a permanent license plate. The plate stays with the trailer for its entire life — you do not replace it or renew it unless the plate is lost, stolen, or damaged. If you sell the trailer, the new owner can transfer the registration into their name by submitting a new process with a bill of sale and their proof of residency.

Keep your registration card with you whenever you tow the trailer. If a law enforcement officer stops you, they will ask to see your driver's license and the trailer's registration. Display the license plate on the back of the trailer so it is clearly visible.

If your trailer is damaged beyond repair or you no longer own it, you can surrender the registration to the DMV. Fill out Form REG 138 (Notice of Nonoperation of Vehicle) and mail it with your registration card and license plate. The DMV will close the registration and you will not owe any further fees.

Special situations: Homemade and imported trailers

If you built your trailer yourself or had one custom-built, you cannot use a manufacturer's certificate of origin. Instead, you will need a Statement of Facts (Form REG 31) signed by a California Highway Patrol officer or a DMV representative who has inspected the trailer. The inspection confirms the trailer is safe and roadworthy. Schedule an inspection appointment at your local DMV office or CHP station — bring the trailer itself so they can examine it.

If you imported a trailer from another state or country, you need the out-of-state title or registration document plus a bill of sale. If the trailer was never registered anywhere, you need a Statement of Facts inspection just like a homemade trailer. Some imported trailers may also require a smog check or brake inspection depending on their age and type, though most utility and cargo trailers are exempt.

Frequently Asked Questions

Do I have to register a trailer if I only use it on private property?

No. California only requires registration for trailers towed on public roads. If your trailer never leaves your property, registration is not required. However, if you ever tow it on a public street, highway, or parking lot, it must be registered.

What if I lost my registration card or license plate?

Contact the DMV and request a replacement. You can do this by mail using Form REG 156 (process for Duplicate Registration Card) or in person at a DMV office. There is a small replacement fee, usually around $20. A new plate will be mailed to you within two to four weeks.

Can I transfer my trailer's registration to someone else?

Yes. The new owner submits a new registration process with a bill of sale signed by you, their proof of residency, and the current registration card. The old registration is cancelled and a new one is issued in their name. The license plate remains the same.

How much does trailer registration cost?

The fee depends on the trailer's dry weight and ranges from roughly $30 for very light trailers to $200 or more for heavy ones. Check the California DMV website for the exact fee schedule by weight class. You pay once and never renew.

What if my trailer does not have a VIN?

Many older and straightforward trailers do not have a VIN. You can still register them — just note on the process that there is no VIN. The DMV will process the registration without one. You will still receive a permanent license plate.