Which swimming style is the slowest?

According to Olympic records over the same distance (100m) the various strokes ranked from fastest to slowest are:

• Freestyle 47.05 seconds• Butterfly 50.39 seconds• Backstroke 51.85 seconds• Breaststroke 57.13 secondsAt longer distances what appears to be relatively close times become much more defined. In other words, out beyond 200m you do NOT want to be doing anything but freestyle for the simple reason that distance covered for energy expended is dramatic.Many years ago I had a student in one of my certification courses to be a Dive Master and she decided that she would do the swim requirement using the breaststroke. I advised against it since it had been a year or two since she had swum competitively at the college level and she had a time limit for the distance. She started strong and faded drastically and missed the time requirement for that distance using that stroke. The following week she used the freestyle and made the distance with time to spare.

Breaststroke is because you need to do it with care.

Breaststroke is the slowest competition wise.

But for me butterfly (I'm really bad at it) or doggy paddle. I can scull faster than doggy paddle (head or feet first)

I don't know the exact name, but I recall a stroke similar to "sculling" where you floated on your back and propelled yourself feet first.

The dog paddle.   

Well, of the four styles used in competion, breaststroke is the slowest