On average, a boat detailing professional is going to charge anywhere from $8 to as much as $40 per foot, depending on what needs to be done, the boat’s size and the condition. The larger the boat is, the more it will cost. For example, a 40-foot boat will cost about $1 to $4 per foot more than a 25-foot boat. Refer to our table below to see what most companies are charging, plus what they are going to include in the quote.