Olympic sprinter speed- 22MPH/35.41 KPH Circumference of Earth @ equator 24,901.55 miles/40,075.16 K
Non-stop around the equator would be 1131.8886 hours.
This does not take into account the time needed to learn to run on water, unless you're Jesus.
Speed and circumference data from Wikipedia.
Or if you're less literal-minded and downright stupid than the above poster and realise that the question does not specify doing it at the Equator, the answer is that it could be done in a matter of seconds at either the North or South Pole. The South would be more sensible, as it is on solid land, rather than the North Pole ice which has become seasonal owing to global warming.