Nationality decides who an athlete may compete for at the Olympic Games; the bye-law to Rule 41 decides when. An athlete who has represented one country in the Olympic Games, in continental or regional games, or in a world or regional championship recognised by the relevant International Federation, and who then changes nationality or acquires a new one, may represent the new country only after three years have passed since that last appearance.
The clock starts at the last appearance, not at the passport
This is the point that catches people out. The three years do not run from naturalisation, from residence, or from a transfer being announced. They run from the last time the athlete represented the former country in one of the listed competitions. An athlete who stopped competing internationally two years before acquiring a new nationality has already spent two of the three years.
The only way to shorten it
The period may be reduced, or cancelled outright, by the IOC Executive Board. It cannot be waived by the athlete's new federation, by the new National Olympic Committee alone, or by the organiser of the event. The Executive Board acts only with the agreement of both National Olympic Committees concerned and of the International Federation for the sport. Three agreements, then a decision.
Where the federations go further
Rule 41 is a floor, not a ceiling. An International Federation may impose its own, longer eligibility conditions, and several do — the waiting periods and match limits differ by sport, and an athlete clear under Rule 41 can still be ineligible under the federation's own rules. The comparison across sports is set out in Changing national team: the waiting period by sport.
What the rule is not about
Rule 41 is not a rule about loyalty and does not ask why the athlete moved. It is a timing rule inside an eligibility system built on nationality, and it exists because the National Olympic Committee, not the athlete, enters competitors at the Games. When a National Olympic Committee loses the capacity to enter anyone — through suspension or withdrawal of recognition — the question stops being about waiting periods altogether, as described in the entry on suspended committees.
Where this is written: Rule 41 of the Olympic Charter and its bye-law, olympics.com/ioc/olympic-charter. The federation rules that sit on top of it are published by each International Federation.