Race Details

Distance: 1 mile

Date: Saturday, June 2, 2018 (Rain date is Sunday, June 17, 2018)

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: $45 before May 5, $55 before May 24, and $65 until June 1. 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: Registration is currently open for our 2018 swim, scheduled for June 2.

  • 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
  • The rain date will be Sunday, June 17.


  • 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 a reasonable amount of 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, the swim might be canceled. In that case, we will send out an e-mail the day before the race and have a notice on this website.


  • Awards, awesome t-shirts and post-race refreshments
  • Bragging rights for having swam a mile in the Charles River!


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.