These include a restyled front bumper and lower grille, and LED running lights beneath the indicators.
Inside, theres smarter trim and new front seats that offer a wider range of adjustment. The centre console box gets a built-in cupholder, while the USB and auxiliary-input sockets have been moved forward to make them easier to reach.
Toyota has also tweaked the chassis and suspension set-up for a better ride.
As before, the standard car does an impressive average of 72.4mpg, and emits just 89g/km of CO2. The T Spirit model gets larger, 17-inch wheels that cut average economy to 70.6mpg and push up CO2 emissions to 92g/km.
Whats the 2012 Prius like to drive?
At low speeds, the Prius can run on electric power alone, but most of the time the 98bhp petrol engine does the work, with the electric motor providing assistance when needed.
Drive goes through a smooth CVT gearbox and acceleration is reasonably perky, but the engine emits a dull drone whenever you push on.
Despite the revised suspension, the larger wheels of our test car transmitted too many bumps and scars into the cabin; thumping over raised manhole covers and broken surfaces quite alarmingly.
The steering, which has been tweaked to provide more feel, still offers little feedback. The handling is safe but uninspiring, and the combination of a stiff pedal action and regenerative braking means its sometimes hard to brake smoothly.
Whats the 2012 Prius like inside?
All trims feature a new touch-screen entertainment system, a rear-view camera and a digital display in the centre of the dashboard that monitors the flow of energy between the engine, electric motor and battery.
The interior is as roomy as ever, and improved by the better-quality plastics, but its still a pretty drab place to spend time.
The new seats are comfortable and have plenty of adjustment, but the steering wheel has limited movement, which can make it difficult to find the right driving position.
The 2012 Prius keeps the spoiler across the rear window, which continues to restrict visibility.
Should I buy one?
The subtle updates to the interior and the exterior improve the appeal of the Prius, and its still an easy car to drive and to own, if not an exciting one.
However, it now faces stiff competition from ultra-efficient diesel cars, such as the Volkswagen Golf 1.6 TDI Bluemotion and the Hyundai i30 1.6 CRDi Blue Drive, both of which are more economical, better to drive and cheaper to buy.
Toyotas future hopes may well rest on the new Prius Plug-In Hybrid, which goes on sale in July and promises greater economy and a much-improved electric-only range.
What Car? says