Home Sanctions WOWSA Rules & Regulations WOWSA 22.0 – MSF Rules

WOWSA 22.0 – MSF Rules

WOWSA supports and accepts the Rules of Marathon Swimming as defined on January 6, 2014 by the Marathon Swimmers Federation for those swimmers who wish to follow its guidelines in ungoverned swims.

However, the rules, guidelines and traditions of existing and future governing bodies are respected by WOWSA. That is, the MSF Rules do not supersede or replace the rules of the Channel Swimming Association, Channel Swimming & Piloting Federation, Catalina Channel Swimming Federation, Farallon Islands Swimming Association, British Long Distance Swimming Association, Irish Long Distance Swimming Association, Lake Tahoe Swimming Society, International Ice Swimming Association, International Winter Swimming Association, Lake Erie Open Water Swimming Association, Santa Barbara Channel Swimming Association, Vancouver Open Water Swimming Association, Northeast Kingdom Open Water Swimming Association, Japan International Open Water Swimming Association, Tsugaru Channel Swimming Association, Menorca Channel Swimming Association, Association of Korea Open Water Swimming, Universal Marathon Cold Swimming Association, Lake Ontario Swim Team, Solo Swims of Ontario, Dubai Open Water Swimming Association, Great Lakes Open Water Swimming Association, Massachusetts Open Water Swimming Association, Asociacion de cruce a nado del Estrecho de Gibraltar, FINA (Fédération Internationale du Natation Amateur), Tsugaru Strait Swimming Association, Hawaiian Channel Swim Association, Kaiwai Channel Association, and other local governing bodies.


The Marathon Swimmers Federation (MSF) Rules of Marathon Swimming are a set of standards and guidelines for undertaking a solo, unassisted open-water marathon swim in any body of water.

MSF Rules may be used by any swimmer who wishes to attempt a swim for which there is no local governing body. They also may be used by local governing bodies wishing to adopt a global standard — or as a foundation upon which to establish local exceptions.
MSF Rules do not override local rules — they aim to codify their shared spirit.

The Spirit of Marathon Swimming

MSF Rules are guided by the traditions and spirit of unassisted marathon swimming.
Marathon swimmers embrace the challenge of crossing wild, open bodies of water with minimal assistance beyond their own innate physical strength and mental fortitude. There are ways to make the sport easier, but marathon swimmers consciously eschew them.

Marathon swimmers take pride that their achievements can be meaningfully compared to the achievements of previous generations, because the standard equipment of the sport has not changed significantly since 1875.


Marathon Swim: A nonstop open-water swim, undertaken according to standardized rules, and requiring at least several hours of sustained effort to complete. Ten kilometers without significant assistance from currents is the minimum distance considered to be a marathon swim.

Nonstop: Remaining in the water for the entire duration of the swim from start to finish without intentional physical contact with escort vessels, support personnel, or other objects (fixed or floating).

Unassisted: Without artificial assistance to performance, other than the standard equipment of the sport. Any swim using nonstandard performance-enhancing equipment, or otherwise violating the rules of unassisted marathon swimming, is considered an Assisted Swim.

Standard Equipment of Marathon Swimming

  • One swimsuit made of porous, textile material. For males, the suit must not extend below the thigh or above the waist. For females it must not extend below the thigh, onto the neck, or beyond the shoulder.
  • One bathing cap made of latex or silicone.
  • Goggles, earplugs, and noseclips.
  • Sunscreen and grease.
  • Escort boat, pilot, and crew.
  • Nutrition, and equipment to transport it between the boat and swimmer. The swimmer may not be supported or towed by the feed equipment.
  • Paddlers and support swimmers.
  • Observer(s)

The swimmer does not need to declare the use of standard equipment (i.e., it is assumed).

Any equipment not specifically listed here is considered nonstandard equipment. Use of nonstandard equipment must always be declared, even if the equipment’s benefit to performance is ambiguous.
Examples of nonstandard performance-enhancing equipment:

Swims using nonstandard, performance-enhancing equipment cannot be considered unassisted. Examples include:
Equipment that may retain or increase warmth – e.g., wetsuits, neoprene caps, booties, gloves.
Equipment that may increase speed – e.g., flippers, paddles, shark cages.
Equipment that may increase buoyancy – e.g., pull buoys, wetsuits.
Auditory pacing aids – e.g., music players, metronomes.
Electronic devices attached to the swimmer, which transmit information to the swimmer – e.g., wristwatches, navigation aids, biofeedback monitors.
Underwater streamers.
Performance-enhancing drugs on the World Anti-Doping Agency List of Prohibited Substances.


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/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:

  • Channel Swimming & Piloting Federation
  • Channel Swimming Association
  • Catalina Channel Swimming Federation
  • Santa Barbara Channel Swimming Association
  • NYC Swim

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.

“Golden Rules” of Marathon Swimming

Transparency of Swim Conduct

The intended conduct of the swim – including Swim Rules and any nonstandard equipment to be used – must be communicated fully and clearly before the swim begins, to everyone involved in the swim attempt, and in all public promotion. The declared rules and equipment may not be changed once the swim has begun.

Independent Observation

Independent and knowledgeable observers must document the facts of the swim and verify the swimmer’s adherence to the Swim Rules.

Swim Rules

This section defines standard MSF Swim Rules for a one-way solo swim (Point A to Point B). Standard rules for multi-leg swims, circumnavigation swims, relay swims, and stage swims are defined in the MSF Rules Supplement.

Individual swimmers or local governing bodies may adopt MSF Swim Rules in full, as shorthand for “standard conduct.” Or, they may adapt the rules to local circumstances, as long as two conditions are met:

  1. Any modifications of standard swim conduct are declared.
  2. The modifications do not violate the spirit of unassisted marathon swimming.

The declared Swim Rules must be read aloud by the observer in the presence of the swimmer and all support personnel before the swim begins.

Start & Finish

The swim begins when the swimmer enters the water from a natural shore. If geographic obstacles (e.g., cliffs) prevent the swimmer from clearing the water at the start, the swimmer may begin the swim by touching and releasing from part of the natural shore (e.g., cliff face).

The swim finishes when the swimmer clears the water on a natural shore, beyond which there is no navigable water. If geographic obstacles prevent the swimmer from clearing the water at the finish, the swimmer may finish by touching part of the natural shore.

Physical Contact

The swimmer may not make intentional supportive contact with any vessel, object, or support personnel at any time during the swim.

Standard Equipment

The swimmer may wear a single textile swimsuit with standard coverage, one latex or silicone cap, goggles, ear plugs, nose clips, and may grease the body. The swimmer may not use any additional equipment that benefits speed, buoyancy, endurance, or heat retention.


The swimmer may not intentionally draft behind any escort vessel or support swimmer. The swimmer may swim alongside an escort vessel, but may not intentionally position him or herself inside the vessel’s bow and displacement waves, except while feeding.
Support Swimmers

A support swimmer (or swimmers) may accompany the solo swimmer for a limited duration. Multiple support swims are allowed, but should not occur consecutively. The MSF recommends a maximum of one hour per support swim and a minimum of one hour between support swims.

The support swimmer may not intentionally touch the solo swimmer and must position him or herself at least slightly behind the solo swimmer.

Authority on the Escort Vessel
The observer is responsible for documenting the facts of the swim, interpreting the swim rules, and keeping the official time.

The pilot of the escort vessel (or lead pilot, if there are multiple vessels) is the ultimate authority in all other matters. (S)he may cancel the swim at any time, for any reason. The pilot is responsible for following all relevant local maritime regulations.

Responsible Environmental Stewardship

Everyone involved in the swim attempt – swimmer, observer, support personnel, and escort boat personnel – must treat the environment respectfully and prevent avoidable harm to marine wildlife and ecosystems.

Continuance of the Spirit of Marathon Swimming
If any issue regarding swim conduct arises that the Swim Rules do not clearly address, the swimmer should act – and the observer should judge – in accordance with the spirit of unassisted marathon swimming.

Using MSF Rules For Your Swim
The MSF Rules of Marathon Swimming are licensed through Creative Commons, and may be used or adapted by individual swimmers or local sanctioning bodies according to the following guidelines:

The Swim Rules section (and only that section) is subject to an Attribution 4.0 International license. You may create adaptations of the MSF Swim Rules, provided you attribute the Marathon Swimmers Federation as the source.
Every other section in this document is subject to an Attribution-No Derivatives 4.0 International license. You may reproduce this content, but only in its original form and only with attribution of the Marathon Swimmers Federation as the source. No modifications are allowed.

End Notes

Linked Documents
Rules Supplement (including Special Swim Types)
Endorsements: Marathon swimmers and organizations who endorse MSF Rules
Press Release for launch of MSF Rules

Rules of Marathon Swimming – Supplement

Special Swim Types

Certain types of swims require additions or modifications to the standard rules for a one-way swim (Point A to Point B). Swimmers and observers should incorporate the indented portions below into their declared Swim Rules, as appropriate.

Multi-Leg Swims

A multi-leg swim is a swim that reaches one or more intermediate destinations (shores) before the final destination.

The simplest form of a multi-leg swim is a two-way (“double”) channel crossing – a swim from one shore to a different, non-contiguous shore, and then returning to the first shore.

However, a multi-leg swim need not return to the original shore. For example, a swim from Island A to Island B to Island C is also a multi-leg swim, with Island A to Island B as “Leg 1” and Island B to Island C as “Leg 2.”

For a multi-leg swim, add the following two rules:

1. After finishing one leg of the swim, the swimmer may rest for up to 10 minutes before beginning the next leg. While resting, the swimmer may be supported by a natural land mass but not by people or artificial objects.
2. Timing of the first leg begins when the swimmer enters the water and ends when the swimmer finishes the leg. Timing of subsequent legs begins at the end of the previous leg and includes any break on shore.

Circumnavigation Swims

A circumnavigation swim is a swim around an island (or islands). For a circumnavigation swim, replace the standard Rule #1 (Start & Finish) with the following:

The swim begins when the swimmer enters the water from the island’s shore. If no beach is available on the island, the swimmer may begin the swim by touching and releasing from part of the island’s shore (e.g., cliff face).

The swim finishes when the swimmer swims around the island and then clears the water beyond the starting point (or touches the island’s shore beyond the starting point, if no beach is available).

If access to the island is restricted, the swimmer may start and finish offshore, as long as (s)he “closes the loop” by swimming beyond the starting point, as measured by GPS.

Relay Swims

A swim undertaken by a team of two or more swimmers, swimming in successive turns of a fixed time interval, in a fixed order.

For a relay swim, add the following two rules:

  1. Relay teams may choose the number of swimmers (six is standard) and the turn interval (one hour is standard), but the team roster, order, and interval must remain fixed for the duration of the swim.
  2. The swimmer exchange takes place in the water, with the new swimmer approaching the previous swimmer from behind. The swimmers are allowed five minutes to complete the exchange, starting from the scheduled exchange time.

Stage Swims

A stage swim consists of two or more “stages,” between which the swimmer rests on shore or on an escort vessel.

For a stage swim, add the following two rules:

Each stage after the first should begin at or behind the finish location of the previous stage.

If the resting location is in open water, the observer must record the GPS coordinates of the stage start and finish locations.

Local Rule Variations in Marathon Swimming

Rules in marathon swimming date to 1927, when the newly-formed Channel Swimming Association wrote its first regulations for English Channel swims. CSA rules (often known as “Channel Rules”) are the basis for most contemporary marathon swimming rules and standards.

Local adaptations of Channel Rules have produced many slight variations on the original. In the absence of a global governing body with global rules, this has sometimes produced confusion about which rules are truly fundamental, and which are open to local modification.

Interestingly, even the “original” Channel Rules are written as local guidelines, not global guidelines. For example, CSA Rules state that after finishing the first leg of a two-way crossing, “Walking 200m along the shoreline to Cap Gris Nez is not permissible.”

The MSF believes there is a fundamental “spirit” shared by the many variations on Channel Rules, and it aims to codify this global spirit while remaining flexible to local adaptations. The MSF also recognizes existing well-established local marathon swimming rules as legitimate adaptations of the global spirit of the sport.

MSF Rules do not invalidate existing local adaptations. Nor should existing local variations necessarily be applied globally.


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