The all new cabriolet was revealed in September 2007 as a four-seat convertible with a soft-top roof.
The full production started in 2008.

The BMW Series 1, also called the E88 was a rear-wheel drive car, offering a choice of four petrol and one diesel engines.

The convertible was based on the already released coupe, however, it was 12mm lower even if the length, width and the wheelbase length remained unchanged.
The soft-top roof could be operated at speeds up to 40 km/h and took 22 seconds to open or close, a bit slower than other cars in the same range, like the Audi A3.
The car was equipped with dual front and front seat-mounted side airbags, ABS, brake assist, ESC, corner braking control, traction control and other systems that made the BMW 1 Series a pretty safe car.

The climate control on this car used an intelligent system that recognized whether the roof is down and adjusted the airflow accordingly. The leather trim was using a Sun Reflective technology that reduced the surface temperature of the seats by 20 degrees.

Even if BMW marketed the convertible as a 4-seater, the rear seats did not offer the passengers enough leg room, thus it was more adequate for kids. The trunk space though offered 260 liters, enough for a trip in the weekend.