The 675LT Spider is priced at $376,700, including a $4,100 destination charge, McLaren spokesman Andrew Brudnicki told Edmunds.
There is no gas-guzzler tax.
Production of the 675LT Spider, which is spun off the 675LT coupe, is limited to just 500 units, the automaker said.
The car is equipped with a three-piece folding hardtop that retracts at speeds up to 19 mph.
Like the coupe version, the 675LT convertible is equipped with a 3.8-liter twin-turbocharged V8 engine that generates 666 horsepower and 516 pound-feet of torque.
It sprints from zero to 62 mph in 2.9 seconds. Top speed is pegged at 203 mph.
McLaren said the 675LT Spider returns 18 mpg in combined city/highway driving.
Buyers can choose an optional Solis exterior paint color that is exclusive to the 675LT Spider.
Two wheel options are available: a 20-spoke design offered in liquid metal or diamond-cut finishes and a five-spoke super-lightweight design that first debuted on the coupe model.
Edmunds says: It's best to get the conversation going with your McLaren dealer now if you want one of these highly desirable convertibles.