There is not a minimum required amount of insurance. The standard liability limits are $100,000, $300,000, $500,000 and $1,000,000. Some companies have liability limits. Your marina may have a minimum liability limit. If you have an umbrella policy, that policy will have an underlying liability limit that you are required to carry.
There are many items that affect your boat insurance premiums, such as where you use the boat. Generally coastal areas cost more than inland areas and areas subject to hurricanes cost more with increased deductibles. Most companies will allow a discount if you complete an approved boating safety course. Having an acceptable driving record can also keep your insurance cost down.
Most of the insurance companies we represent have discounts for successfully completing an approved safe boating course. Courses approved by the National Association of State Boating Law Administrators (NASBLA), include courses by the Coast Guard Auxiliary, Power Squadron and others.