Depends on the stroke...
http://www.swimmingwithoutstress.co.uk/swimming-blog/are-you-a-head-up-breaststrokersweimming stokes - putting head in water
(from link:)
Head up breaststroke puts a lot of strain on the neck and back and makes relaxed breathing impossible. It may do more harm than good. In the UK, a lot of women swim like this.
If you swim for exercise but don’t get your hair wet, here are 6 reasons why it’s not a good idea:
1. You can’t breathe well because your neck is constricted.
2. You’re risking neck and back problems. Imagine walking around for 20 minutes looking right up at the ceiling. This is the sort of position your head is in when swimming head up breaststroke.
It does indeed.
But for open water races they do a freestyle, during which their head stays in the water with the face rotating left and right for breaths.