Additional Driver on a Rental Car in California 2026: Who Is Exempt and What It Costs
Updated October 30, 2026 · By Yaniv Segal, RentCarUSA
In short: In California the law does not allow rental companies to charge an additional driver fee for the renter's spouse, child, sibling, parent or grandparent, or for an employer or co-worker. A friend, cousin or parent-in-law is a regular additional driver, and at the large companies the fee is usually around $13–$15 per day. In every case, everyone who drives must be listed on the contract.
What exactly does California law say about additional drivers?
The rules are in the California Civil Code, section 1939.19, as amended by bill AB 901, signed in September 2021. According to the text, a rental company may charge a fee for an additional authorised driver, unless the driver is one of the following:
| Relationship to the main renter | Additional driver fee in California |
|---|---|
| Spouse | Exempt by law |
| Child (including legal guardianship) | Exempt by law |
| Brother or sister | Exempt by law |
| Parent | Exempt by law |
| Grandparent | Exempt by law |
| Employer or co-worker (on a work trip) | Exempt by law |
| Friend, cousin, uncle or aunt | Usually paid |
| Parent-in-law, brother-in-law, sister-in-law | Not on the list, usually paid |
| Unmarried partner | Depends on the definition and the branch policy; ask in advance |
Note the direction of the relationship: the list is measured in relation to the main renter, meaning the person whose name is on the contract and the card. If the father rents and the son drives, the son is exempt. If the son rents and wants to add his mother-in-law, she is not on the list.
The law also states that if the rental company finds that an additional driver who was not registered drove the car, it may charge up to twice the additional driver fee. That is the small penalty. The big problem is insurance, which we explain below.
The exemption saves money, but not the registration
An exemption from the fee does not mean your partner can drive without being registered. For an additional driver, even an exempt one, to count as an "authorised driver":
- They must be listed on the rental agreement. This is usually done at the branch on the day of pickup.
- They must come to the counter with a valid driving licence and usually also a passport. With us, a valid licence from your home country is enough for the additional driver too. If the licence is not in the Latin alphabet, or only partly in English, read the guide to foreign driving licences in California.
- They must meet the age requirement. Our minimum age is 21. An additional driver aged 21–24 pays a daily young driver surcharge, exactly like a main driver of that age, even if they are exempt from the additional driver fee. Details are in the guide to car rental under 25.
- The additional driver does not need their own credit card. The deposit hold is placed only on the main driver's card.
What happens if someone who is not on the contract drives?
This is the situation to avoid. The damage cover and third-party liability included in the rental apply to authorised drivers. If an unregistered driver has an accident, the rental company may claim the cover does not apply, and the main renter will face a claim for the damage to the car and the damage to the third party. In California, with American car and medical prices, these amounts can reach tens or hundreds of thousands of dollars.
A very common example: a family comes for a month, a relative joins in the second week and "just drives one section" on Highway 1. If there is any chance that another person will drive, add them. It is cheapest when it is done in advance, and for a close family member in California it usually costs nothing at all.
How much does a non-exempt additional driver cost?
At the large US rental companies, the additional driver fee is usually around $13–$15 per day, and some companies have a cap for the whole rental period. Over a 26-day rental, this can add up to a significant amount if there is no cap, so it is important to know the number before you reach the counter.
| Scenario (26 days) | What to expect |
|---|---|
| Married couple, both 25+ | The second driver is exempt from the additional driver fee by law |
| A parent and two adult children, all 25+ | The children are exempt from the additional driver fee |
| Two friends aged 23 | Additional driver fee for the friend, and young driver surcharge for both |
| A couple and a cousin who joins for a week | Additional driver fee for the cousin, usually per day or according to the branch terms |
With us there are no surprises at the counter: tell us in your quote request who will drive and the age of each driver, and we will include it in the quote. The amount you pay will never be higher than the quote.
Tips for an additional driver on a long trip in California
- Share long drives. Los Angeles to San Francisco on Highway 1, or Los Angeles to the Grand Canyon, are days of 6–8 hours of driving or more. Two registered drivers are a matter of safety, not only comfort.
- The additional driver needs to know the rules. Turning right on a red light, a full stop at a 4-Way Stop and carpool lanes may be different from what they know at home. They should also read the guide to driving in Los Angeles for visitors.
- Keep the contract in the car or on your phone. If a police officer stops the additional driver, they will ask for a licence, and sometimes also for the car documents and the rental agreement.
Frequently asked questions
My wife will not be at the branch on the day of pickup. Can I add her later?
Usually you can add a driver at the company's branch during the rental, when they come with a licence and passport. It is better to plan for her to come to the pickup. Until she is registered, she does not drive.
My son is 20. Can he be an additional driver?
No. Our minimum age for every driver is 21, and drivers aged 21–24 pay a young driver surcharge.
Does California law also apply to visitors with a foreign licence?
The law applies to car rentals in California, regardless of the renter's citizenship. The family relationship decides the exemption, not the passport.
Do I need to prove that the additional driver is really my brother or parent?
Sometimes the branch asks for proof, especially when the family name is different. It is a good idea to have a photo on your phone of a document that shows the relationship, such as a birth certificate or an official family record.
Tell us who will drive and get a quote that includes all drivers, or read the guide to monthly car rental in Los Angeles.