"Athletes are required to maintain the accuracy of their whereabouts information at all times," the Australian Sports Anti-Doping Authority (ASADA) said in a statement on Thursday.
"Mr Poort failed on two occasions to submit his information on time, and on the third occasion, ASADA attempted to test Mr Poort outside his designated hour, only to discover that he had not updated his whereabouts to take account of travel plans."
Poort, who competed in the 1,500 metres freestyle in London and 10km open water swim four years later in Rio, could have been banned for two years but ASADA decided he had not deliberately intended to deceive.
"At the end of the day people make mistakes and that's what I did," Poort, who has waived his right of appeal, said in a Swimming Australia media release.
"It was remiss of me to neglect a management system that must be shown the full respect it deserves and it is a very embarrassing situation to now be in."
(Reporting by Nick Mulvenney, editing by Ian Ransom)
