The standard upholstery in the five-occupant interior has a slightly coarse woven feel said to be inspired by sportswear. Leather upholstery is available. Volvo says storage space is improved both in the door pockets and center console. The center armrest is modified for greater comfort, and the handbrake handle is smaller and less intrusive. The T5's instruments are redesigned for 2008 with watch-style gauges. Nordic Light Oak trim is now optional on the 2.4i; the T5 has aluminum trim.

The rear seatbacks fold down separately, and the front passenger seat's backrest also folds flat. Standard 2.4i equipment includes air conditioning, power windows, power locks with remote keyless entry, and a leather-wrapped tilt/telescoping steering wheel. The S40's auxiliary stereo input for MP3 players is now standard equipment. A single-CD player with steering-wheel stereo controls is standard, but buyers can upgrade to an in-dash six-CD changer. Sirius Satellite Radio is standard on the T5 and optional on the 2.4i and includes six months of free service.

The T5 sedan adds a power driver's seat, electronic climate control, a trip computer and aluminum interior trim. An optional Premium Package for the T5 includes leather seating surfaces, a power sunroof and a power passenger seat, among other items. T5 options include keyless ignition, a sport steering wheel and gearshift knob, a new premium stereo, a GPS navigation system and active xenon headlights that swivel in the direction of a turn. The previous option's were fixed.