Optional wood trim is found on the passenger dashboard, lower console, gear shift lever and door panels, but unlike many luxury cars, not on the centre control panel. The centre dash area is 'Swedish' grey in colour with protruding round dials and buttons for the climate control, seat heaters, and rear defroster. A driver information display on the instrument panel is operated by a round dial on the dash - it includes trip computer, fuel consumption, and outside temperature gauge. The headlight switch is located on the left side of the dash, along with buttons for front and rear foglights. The front cupholder has a sping-loaded cup gripper, but the gripper gets in the way when trying to insert the cup.
Rear passengers have a folding centre rear armrest and map pockets on the seatbacks.
For a small car, the S40 has a surprising amount of cargo-carrying versatility. In addition, the front passenger seatback folds flat, allowing long objects, like ladders, to be carried inside the car. The S40 has more standard safety features than other cars in its price range. The outer rear seats can be fitted with integrated child booster cushions for older children, and the split-folding rear seat has been designed to withstand forces exerted by the luggage behind it during a collision. S40's also offer active safety features, such as anti-lock brakes with Electronic Brake Distribution, and optional Dynamic Stability Assurance, a system that monitors and compares the rotational speed of all four wheels and uses the engine management system to reduce torque when it detects a loss of traction.