The swim observer documents the facts of a swim and verifies the swim’s adherence to the declared rules. Documentation produced by a qualified observer is the single most important source material for authenticating a swim claim.


The primary qualifications of an observer are:


The observer must be capable of dispassionately evaluating the swim and its adherence to the declared rules. If the observer is acquainted with the swimmer, (s)he must be able to separate the personal relationship from his or her duties to observe, document, and verify.


The observer must be knowledgeable about the rules, traditions, and spirit of marathon swimming, and with the responsibilities of observing a marathon swim.

The MSF maintains a global network of qualified, willing observers. Local observer networks and official trainings are offered by following organizations:

Observers who have not attended an official training may also demonstrate expertise through their personal history in the sport - as a swimmer, crew-member, or administrator.

Special Considerations

Very Long Swims

If a single observer is not able to maintain alertness for the entire duration of the swim, an additional observer is necessary. The MSF recommends two observers for swims anticipated to last longer than 18 hours, and three observers for swims anticipated to last longer than 30 hours. Overnight swims in the 10-18 hour range may also require a second observer.

On swims with multiple observers, a lead observer should be designated to coordinate the observer team and documentation procedures.

High-Profile or Unprecedented Swims

Swims of unusual magnitude or notoriety - especially unprecedented swims - demand a stricter standard for observer qualifications and reputation. In such cases, it is essential that the observers are trusted by the broader community of marathon swimmers.

The MSF recommends a minimum of two highly qualified, reputable observers for high-profile swims, to reinforce their credibility.

This page is from “Rules of Marathon Swimming” by Marathon Swimmers Federation. The page is licensed under the CC BY-ND 4.0 license. ©2012-2023 Marathon Swimmers Federation.