Castle 2.5K/5K/10K 2025
Online Registration has Closed
About
The Castle 2.5K/5K/10K is the highest altitude organized marathon swim event in the country at ~8,000 feet. It is hosted at Wellington Lake, near Conifer in Colorado.
Sign up to Volunteer
Race Day Schedule will be shared closer to event date.
Distances:
- 2.5K
- 5K
- 10K
T-shirts are not guaranteed. We close t-shirts around 2 weeks before the race.
If you plan on Camping, but have already signed up for the race, please click on “SHOP” above. This will allow you to select a camping site for Friday night (August 22), Saturday night (August 23), or for both nights (August 22 & 23). Camp Sites will fit 1 vehicle and 4 persons only. No RVs, trailers, or teardrop campers, cars/trucks only.
We will close online registration when we have reached our parking cap for this race (250 participants)
All packet pickup will be the morning of the swim. Please plan to come and pick up your packets early!
Early Bird Registration Closes March 1. Race prices will become full price on that date.
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Registration Closed2.5kSaturday, August 23, 20258:00 AM
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Registration Closed5kSaturday, August 23, 20258:00 AM
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Registration Closed10kSaturday, August 23, 20258:00 AM
Series Passes
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Series Pass
The Mountain Swim Series is excited to be coming into its eleventh year in 2025! This series provides experienced and organized Open Water Swimming to the Rocky Mountain Region. Prizes are provided for the top three males and females in both wetsuit and non-wetsuit divisions for each race and for overall series winners at the end of the year. This series offers the opportunity to swim and race in the open water at over a mile high in elevation.
The 2025-series will consist of FIVE events.
All Mountain Swim Series events will be insured and supported by safety watercraft, lifeguards, and paramedics/EMTs, however, any person signing up for these events should be a competent swimmer in good health and be able to consistently hold a 2:30 per 100 yard pace or faster.
See you in the water!!!
Series pass includes:
● Solstice Sunrise Swim 2025
● Castle 2.5K/5K/10K 2025
● Wellington Swim-Run 2025
● Willow Creek 2025
● Carter 2025
