MSF Rules

The simple answer is that I want to officially accomplish an ultra-marathon distance swim following the rules adopted by the community to represent 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 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 Swimmers Federation, " The Spirit of Marathon Swimming"

I have not completed a marathon swim in the full spirit of marathon swimming. I've always used a buoy and swam with as many people as I want. I like the idea of pushing through the mental challenge of not being able to high-five buddies or being surrounded by a pod. Documentation of these sorts of swims is essential for building a marathon swim resume that will open doors to future long swims that require qualifying swims(s); such as the English Channel, or 20 Bridges (formerly Manhattan Island Marathon Swim).

For convenience, the sections below reproduce information from the Marathon Swimming Federation Rules section. Links will open to specific documents as indicated.


"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." - Marathon Swimming Federation Rules: Observers

If you are interested in observing, PLEASE see MSF website for more information.

If you observe, we will go over everything in more detail.

Swim Rules

The below is taken directly from the MSF website:

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. The pilot may cancel the swim at any time, for any reason, including, but not limited to, concerns for the safety of the swimmer or support personnel. 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.

Documentation Requirements

Again, taken directly from the MSF site: Documentation Requirements also see Marathon Swims

Summary of Requirements

  • Basic Facts of the Swim - swimmer bio details, support crew, observer, route definition, rules.

  • GPS Tracking Data - original, raw data from tracking device

  • Narrative account of swim by observer and/or swimmer

  • Photos and Video

  • Observer Log - regular timestamped observations of water temp, air temp, wind speed, stroke rate, and other notes

The following types of swims are not eligible for ratification:

  • Swims assisted by nonstandard equipment, e.g., wetsuits, fins, GPS watches, tow floats.

  • Non-repeatable swim routes or routes defined by non-permanent markers such as buoys.

  • Swims shorter than 10km, or multi-way swims where no individual segment is 10km+ (unless specifically approved by MSF).

  • Swims witnessed by a single person.

  • Swims governed by an existing local marathon swimming association.

Download Observer Log Sheet

Download Observer Log Instructions

Examples of well documented swims

These are quite a few well-documented river swim examples, below are two from 2019.

Go to the Marathon Swims page and view "Ratified swims" by year.

Ned Hastings - Columbia River Great example of documentation here in the PNW.

Ross Youngman - Derwent River