There were 19 NOC that medaled in swimming events. 166 of the 204 NOCs had athletes in the 34 swimming events see related link
10,820 athletes from 204 countries competed in the 2012 London Olympics.
olympics london 2012
There are 10,960 athletes participating in the London Olympics. 6098 are men . 4862 are women.They are from 205 countries.
Total of 10,820 athletes competed at the 2012 London Olympics.
204
Oscar Pistorius
At the 1948 Games in London, women competed in art competitions, athletics, canoeing, diving, fencing, gymnastics, and swimming.
Singapore first competed in the Olympics at the 1948 Summer Games in London.
He will have competed in 4 Olympics after the London 2012 Olympics.
In the 2012 London Olympics the Dutch competed in yellow/orange colored rowing boats. This may vary between the different rowing events they competed in.
32 countries are participating in archery at London Olympics.
204 countries participated in the 2012 London Olympics.