Race Details

Distance: 1 mile

Date: Saturday, June 18, 2022. The rain date is the following day, Sunday, June 19, 2022.

Start: 8am

Check-in: 6:45am – 7:20am

Location: River Dock (near Arthur Fiedler head statue by the Hatch Shell on Esplanade)

Description: One-mile loop course between Harvard and Longfellow Bridge. Water start.  Please see maps.

Fees: Registration will open on March 21.  The fee is $45 until April 31, $55 until May 31, and $65 until June 17 when registration closes.  Sign up early to save on fees!  There is no race day registration. USMS membership is a requirement and a one-day membership can be purchased as part of the registration process for $15.

Participant cap: 200 swimmers

Registration: Register at www.runsignup.com!

  • Only pre-registered swimmers are allowed to compete.
  • Water temperature: Has historically been 70 degrees or above but can vary based on spring weather patterns.
  • Wetsuits are allowed, unless the water temperature exceeds 78 degrees (per USMS rule).
  • Other assistive devices, including masks, fins, snorkels, and paddles are not allowed.
  • Swimmers are not permitted to wear headphones during the race.
  • This swim is not for novices; it is for experienced open-water swimmers only. At a minimum you should be able to swim one mile comfortably in under 40 minutes.
  • USMS membership is required. Day-long membership is $15 and can be purchased as part of the online registration.
  • Age requirement: 18 years minimum
  • Kayakers will provide support during the race
  • Fluorescent swim caps will be provided and must be worn for safety reasons
  • Mandatory Athlete check-in from 6:45am to 7:20am, please bring a photo ID.
  • Pre-race announcement at 7:40am
  • Start 8am
  • Bag-check available


  • This swim is not for novices; this event is for experienced open-water swimmers only. To participate, you should be able to swim one mile comfortably in 40 minutes or less.
  • The race director reserves the right to pull swimmers from the water who cannot complete the course in the allowed time.  This is for safety reasons, as boat traffic must resume along the river immediately following our event.
  • The race is dependent on weather conditions and may be canceled under adverse conditions. Swimmers may encounter random jetsam and flotsam in the river.


  • In the even of heavy or prolonged rainfall during the days prior to the race, the swim might be canceled. In that case, we will send out an e-mail the day before the race and post a notice on this website.


  • In addition to this page be sure to read our Race Policies page.


  • Awards, super awesome t-shirts, and post-race refreshments
  • Bragging rights for swimming in the Charles
  • A generally amazing location to hang out after a morning swim and connect with other river-loving friends


We suggest you arrive by public transportation, biking or walking. The closest MBTA station is the Charles/MGH station on the Red Line or Arlington or Copley Station on the Green Line. Take the Arthur Fiedler footbridge or the Charles/MGH footbridge. Pay parking is available at the Boston Common garage.