I was watching the return of Scott Kelly to earth from the ISS, I noticed that when the crew entered the Soyuz, they didn't wear spacesuits (https://youtu.be/saE0JGtIEKE?t=7m13s) but when they are back on earth they are wearing spacesuits (https://youtu.be/dWCqzPksYyY?t=9m48s). I noticed a boot in the Soyuz (you can spot it at the hatch of the first video) so I am guessing they suit up in the Soyuz. Since there isn't a lot of space in the Soyuz, my question is: How (and when) do they suit up?
After depressurizing the vestibule, we observed for a few minutes the pressure indications for the descent module and the orbital module of our Soyuz: both stable, so there was no obvious, fast leak. (Not that we were expecting one!).
Of course we needed to check for a slow leak as well, before we committed to leaving the Station and relying on the Soyuz hatch to keep our air inside. The full leak check would take 30 min, with measurements of the vestibule pressure recorded every 5 min, but since there was no fast pressure drop it was safe for us to reopen the hatch of the descent module and float back to the orbital module to don our Sokol suits. (...)
There's an interesting blog entry describing the return to Earth for an earlier expedition.
Here's a quote from the most relevant part:
Gennady, Andreas and Aidyn will put on medical telemetry belts and tight-fitting shorts called the Kentavr to stop blood from the legs flowing to the head during reentry. Afterwards they will put on their Sokol pressure suits in the orbital module.
All of these procedures seem to occur after hatch closing (there isn't an accurate timeline.)
There are some other interesting items described too, such as various cabin leak checks, a suit leak check, breathing exercises for re-entry...