There’s more than enough space for a couple of tall adults in the front, with particularly good head and leg room and reasonable interior width, so you're not butted up to your passenger. And it has plenty of cubbyholes in which to stow odds and ends, such as under the front armrest, in the decent-sized glovebox and in drawers under the front seats.
There’s space for three in the back, but if all three are broad adults, it’ll be a squeeze. If it’s just two, only super-tall folk are likely to grumble about leg or head room. Indeed, the Cupra is on a par with the likes of the Volkswagen Golf R, but the Ford Focus ST and Honda Civic Type R are noticeably more spacious in the back.
Boot size depends on whether you go for the hatchback or estate. The hatchback has a 380-litre boot, which is similar to the Golf R’s but no match for the Civic Type R’s. It'll take a couple of large suitcases or a child’s buggy, and you get a height-adjustable boot floor to smooth out the step that's formed when you fold the 60/40 split rear seats.