A standard auto insurance policy will extend to most types of trailers that you tow with your insured car or truck. This includes the liability portion of your auto insurance policy, which means that if you damage someone's property while backing up your trailer, your insurance company will cover you up to your policy limits. Each auto insurance company handles trailer coverage differently, so contact your insurer before assuming that your policy covers any specific type of incident.
Some auto insurance companies require customers who tow trailers to purchase additional coverage. You can keep your standard auto insurance, but you won't be covered if your trailer needs repair following an accident if you cause damage or injury with your trailer. This is the case if your insurance offers add-on coverage, allowing you to add your trailer -- along with limits up to its full value -- to your policy. You will also need to buy new coverage if your auto insurance doesn't cover the particular type of trailer that you plan to use. You can purchase a separate policy for your trailer from another insurance company or shop around for a new insurer that offers trailer coverage as part of its standard auto insurance products.
Self-powered recreational vehicles and travel trailers fall under the heading of motor vehicles, which means you need the same insurance that your state requires you to have for a conventional vehicle. States that require auto insurance will not issue registration documents or license plates for motor vehicle trailers that lack insurance. As with conventional auto insurance policies, rates will depend on the driver's age and driving record, as well as the value of the trailer.
In certain special cases, you can get insurance for a trailer through other means. For example, if you own a business and tow a trailer on a regular basis to perform your work, your business insurance should include coverage for not only your fleet of vehicles but also any trailers you use. If you own a boat and use a trailer to tow it to and from launch sites, your boat's insurance policy should extend to the trailer.