What you need to register a trailer in California
Trailer registration in California is handled by the Department of Motor Vehicles (DMV), and the process depends on whether your trailer is new or used, and what you plan to use it for. Most trailers — including utility trailers, boat trailers, and RV trailers — need a certificate of ownership and a registration certificate before you can legally tow them on California roads. The DMV charges a registration fee based on the trailer's age and weight, and you'll need to renew it every two years.
You cannot register a trailer without proof of ownership. If you bought it new, you'll have a manufacturer's certificate of origin. If you bought it used, the seller must give you a signed pink slip (the back half of the title) or a bill of sale if the trailer has never been titled in California. You'll also need your California driver's license or ID, proof of residency (like a utility bill or lease), and the vehicle identification number (VIN) from the trailer itself.
Key Takeaways
- California requires all trailers to be registered with the DMV before you can legally tow them, and registration must be renewed every two years.
- You will need the pink slip (title) from the previous owner, your driver's license, proof of residency, and the trailer's VIN to complete registration.
- Registration fees vary based on the trailer's age and dry weight, and you can pay them when you register in person at a DMV office or through the mail.
- If your trailer weighs more than 10,000 pounds, you may need a commercial registration and a different type of license plate.
How to register a trailer at the DMV
Start by gathering your documents: the pink slip or bill of sale, your driver's license, proof of residency, and the trailer's VIN (usually stamped on the frame near the tongue). You can register in person at any DMV office, by mail, or online through the DMV website if you meet certain conditions — primarily that the trailer is not new and you are not a first-time registrant in California.
If you register in person, bring all documents and be ready to pay the registration fee at the counter. The DMV will inspect your documents, assign a registration number, and issue you a certificate of registration and license plate. If you register by mail, send copies of your documents and a completed process for Title or Registration (Form REG 343) to your local DMV office. Processing by mail typically takes two to three weeks.
Online registration through the DMV website is the fastest option if you are renewing an existing registration or registering a used trailer you already own. You will need to create a DMV online account, upload images of your documents, and pay the fee with a credit or debit card. The DMV will mail your registration certificate and plate to your address within one to two weeks.
Registration fees and what affects the cost
California registration fees for trailers are based on the trailer's dry weight (the weight without cargo or water) and its age. A light utility trailer under 1,500 pounds costs less than a heavy equipment trailer over 10,000 pounds. The DMV publishes a fee schedule on its website that shows the exact cost for each weight category.
In addition to the base registration fee, you may owe a vehicle license tax, which is a one-time fee calculated as a percentage of the trailer's market value. This applies to trailers registered for the first time in California or trailers you are registering after moving to the state. The DMV will calculate this amount based on the purchase price you report on your registration form.
If your trailer weighs more than 10,000 pounds, you will need a commercial registration instead of a standard registration. Commercial registrations cost more and require a different license plate. You may also need a commercial driver's license (CDL) depending on the total weight of your vehicle and trailer combined — this is a separate requirement from the DMV and depends on your state of residence and the type of cargo you carry.
Renewing your trailer registration
Trailer registrations in California expire every two years on the date shown on your registration certificate. The DMV will mail you a renewal notice about 60 days before your registration expires. You can renew by mail, online, or in person at a DMV office.
To renew online, log into your DMV account, select your trailer, and pay the renewal fee with a credit or debit card. The DMV will mail your new registration certificate and plate (if needed) within one to two weeks. Renewing by mail requires the same form (REG 343) and takes about two to three weeks. If you renew in person, bring your current registration certificate and driver's license, and you will receive your new certificate when ready.
If your registration has already expired, you can still renew it at the DMV, but you may face a late fee in addition to the standard renewal cost. Do not tow your trailer on California roads with an expired registration — you can be cited and fined.
Special situations: new trailers and out-of-state transfers
If you bought a new trailer from a dealer in California, the dealer often handles the registration paperwork for you as part of the sale. You will receive the manufacturer's certificate of origin and a temporary registration permit that allows you to tow the trailer home. You must complete the permanent registration within 30 days by submitting the certificate of origin to the DMV along with your other documents.
If you are moving to California with a trailer registered in another state, you must register it with the California DMV within 20 days of establishing residency. Bring your out-of-state title, your driver's license, proof of California residency, and the trailer's VIN. The DMV will issue you a California title and registration. Some states have reciprocal agreements with California that may reduce or waive the vehicle license tax, so ask the DMV clerk whether your situation qualifies.
License plates and identification for trailers
When you register a trailer in California, the DMV will issue you a license plate specific to that trailer. The plate format depends on the trailer's weight and use. Standard trailers receive a white plate with black numbers and letters. Trailers over 10,000 pounds receive a commercial plate, which is different in appearance and indicates the trailer requires commercial registration.
You must display the license plate on the back of your trailer in a location that is clearly visible and not obscured by cargo or equipment. The plate must be kept clean and legible at all times. If your plate is lost, stolen, or damaged, you can request a replacement from the DMV for a small fee.
Your trailer's VIN is also important for identification and ownership verification. Keep a record of your VIN in a safe place, separate from the trailer itself. If your trailer is stolen, you will need the VIN to file a police report and to work with your insurance company.
What happens if you don't register your trailer
Towing an unregistered trailer on California roads is illegal and can result in a citation, fine, and impound of the trailer. Law enforcement officers can stop you if they see a trailer without a visible license plate or with an expired registration. The fine for operating an unregistered vehicle in California can range from $100 to several hundred dollars, depending on the violation and whether it is a first or repeat offense.
If your trailer is impounded, you will need to pay an impound fee plus daily storage fees to retrieve it. You will also need to complete registration before the trailer can be released. If you believe your registration has lapsed or you are unsure of your registration status, you can check online through the DMV website by entering your license plate number or VIN.
Frequently Asked Questions
Do I need to register a trailer if I only use it occasionally?
Yes. California law requires all trailers to be registered regardless of how often you use them. Even if you tow your trailer only a few times a year, it must have a current registration and license plate displayed. An unregistered trailer cannot legally be towed on any California road.
What is the difference between a pink slip and a bill of sale?
A pink slip is the official title document issued by the DMV and shows ownership history. A bill of sale is a receipt signed by the seller stating they sold you the trailer. If the trailer has never been registered in California, the seller may give you a bill of sale instead of a pink slip. Either document is acceptable for first-time registration, but you will need to explore for a California title at the same time.
Can I register a trailer without a VIN?
No. The VIN is required to register any vehicle or trailer in California. If your trailer does not have a visible VIN or the number is illegible, contact the DMV before attempting to register. The DMV may require a VIN inspection by a certified inspector before registration can proceed.
How long does it take to get a registration certificate in the mail?
If you register by mail, expect two to three weeks for processing and delivery. If you register online, the DMV typically mails your certificate within one to two weeks. In-person registration at a DMV office is fastest — you receive your certificate when ready, though you may wait in line at the office.
What if I sell my trailer — do I need to do anything with the registration?
Yes. When you sell your trailer, sign the back of the title (pink slip) and give it to the buyer. You should also notify the DMV that you no longer own the trailer to avoid liability if the new owner is involved in an accident or violation. You can do this by mailing a signed notice to the DMV or by completing a release of liability form at a DMV office.