The 39-year-old’s ban runs until May 17, 2020.
Schoeman won gold in the 4×100 freestyle relay at the 2004 Athens Games plus individual silver and bronze medals in the 100 and 50m freestyle. He also competed in the 2000, 2008 and 2012 Olympics.
The triple world champion failed to qualify for the 2016 Rio de Janeiro Olympics but had said last year he was still hoping to qualify for one more Games.
FINA said Schoeman tested positive for the prohibited substance GW501516, a hormone and metabolic modulator, at an out-of-competition control on May 18 last year.