While we make every attempt to ensure the accuracy of our multisport calendar, we recommend that you verify the date, time, location and distance of an event before making the journey. If you spot any errors or omissions in our race calendar, please let us know.

A Racing Underground Owned Event

A Racing Underground Timed Event

An AMB Chip Timed Event

• 14 - Pedal Power Winter Triathlon - (5k Snowshoe/10k Bike/8k Ski) - Tennesee Pass Nordic Center - Ski Cooper, Colorado - 10:00 a.m. - 970-845-0931

  ---

• 21 - Chilly Cheeks Duathlon Series #2 (1.5M Run/3.6M Bike/2.5M Run/7.2M Bike) - Cherry Creek State Park, Denver, Colorado - 303-642-7917
  

  ---

• 22 - t2coaching Indoor Triathlon - (15m Swim/15m Bike/15m Run) - Fort Collins Club - Fort Collins, Colorado - 7:30 a.m. - 970-308-4499

  ---

• 4 - Street Swell Winter Triathlon - (5k Snowshoe/10k Bike/8k Ski) - CMC Timberline Campus - Leadville, Colorado - 10:00 a.m. - 970-845-0931
• 18 - Mt. Taylor Winter Quadrathlon - (12M bike/5M Run/2M Ski/2M Snowshoe/4M Ski/5M Run/13M Bike) - Grants, New Mexico - 800-748-2142

  ---

• 25 - Chilly Cheeks Duathlon Series #3 (10.8M Bike/4M Run) - Cherry Creek State Park, Denver, Colorado - 303-642-7917
  

  ---

• 4 - t2coaching Indoor Triathlon - (15m Swim/15m Bike/15m Run) - Fort Collins Club - Fort Collins, Colorado - 7:30 a.m. - 970-308-4499
• 10 - Steamboat Pentathlon - (400' Downhill Ski/3M Snowshoe/4M XC Ski/12M Mtb/5M Run) - Shorter courses available - Steamboat Springs, Colorado - 970-879-4300
• 31 - Pole, Pedal, Paddle - (Backcountry Skiing - Mtn Biking - Kayaking) - Monarch Pass to Salida, Colorado - 719-221-1710

  ---

• 15 - Tri the Rim Triathlon - (500Y Swim/12M Bike/4M Run) - Lewis Pool - Durango, Colorado - 970-247-7220
• 29 - t2coaching Indoor Triathlon - (15m Swim/15m Bike/15m Run) - Fort Collins Club - Fort Collins, Colorado - 7:30 a.m. - 970-308-4499

---

• 12 - Barkin Dog Duathlon - Mile High Duathlon Series #1 - (5k Run/30k Bike/5k Run) (1M Run/10M Bike/5k Run) - Cherry Creek State Park, Denver, Colorado - 7:15 a.m. - 303-642-7917
  

  ---

• 19 - Summer Open Sprint Triathlon - (800m Swim/12.4M Bike/5k Run) - Union Reservoir - Longmont, Colorado - 303-408-1195
  

  ---

• 20 - Tri The Rock Youth Triathlon - (various distances) - Butterfield Park - Castle Rock, Colorado - 8:00 a.m. - 720-733-2284

  ---

• 26 - Pelican Fest Sprint Triathlon - 800m Swim/11M Bike/5k Run) - Windsor, Colorado - 970-308-4499
  

  ---

• 1 - Metro Brokers Triathlon - (0.5M Swim/12M Bike/3M Run) - Cherry Creek State Park - Denver, Colorado - 6:00 p.m. - 303-843-0100

  ---

• 2 - City of Longmont Kids Triathlon - (various distances) - Centennial Pool - Longmont, Colorado - 303-774-4759
  

  ---

• 3 - Longmont Triathlon - (525m Swim/12M Bike/5k Run) - Centennial Pool - Longmont, Colorado - 303-774-4759
  

  ---

• 7 - Boulder Stroke & Stride Series #1 - (750m Swim/5k Run) (1500m Swim/5k Run) (or just the 5k Run) - Boulder Reservoir - Boulder, Colorado - 6:00 p.m.- 303-642-7917
  

  ---

• 9 - Big Sky Duathlon - (4k Run/25k Bike/4k Run) - Community Center - Bennett, Colorado - 8:00 a.m. - 303-642-7917
  

  ---

• 9 - Tune Up Sprint Triathlon - (500m Swim/12M Bike/5k Run) (kids:various distances) - Westbridge Recreation Center - Highlands Ranch, Colorado - 6:00 a.m. - 303-791-2500
• 9 - Highline Hustle Triathlon - (500m Swim/16M Bike/3M Run) - Highline Lake State Park - Loma, Colorado - 7:30 a.m. - 970-254-3893
• 9 - Outside in Aspen Triathlon - (500m Swim/10M Bike/5k Run) (5k Run/10M Bike/5k Run) (800Y Swim/17M Bike) - Recreation Center - Aspen, Colorado - 970-429-2093
• 10 - Greeley Triathlon - (5oom Swim/10M Bike/5k Run) - Promontory Park - Greeley, Colorado - 7:00 a.m. - 970-351-1814
• 10 - Foothills Feat Mini Sprint Triathlon & Kids Triathlon - (275Y Swim/10M Bike 2.25M Run) (kids: various distances) - Foothills the Ridge Recreation Center - Littleton, Colorado - 7:00 a.m. - 303-579-9488

  ---

• 14 - Boulder Stroke & Stride Series #2 - (750m Swim/5k Run) (1500m Swim/5k Run) (or just the 5k Run) - Boulder Reservoir - Boulder, Colorado - 6:00 p.m.- 303-642-7917
  

  ---

• 17 - 5430 Sprint Triathlon - (0.5M Swim/17M Bike/5k Run) - Boulder Reservoir, Colorado - 813-868-5940

  ---

• 21 - Boulder Stroke & Stride Series #3 - (750m Swim/5k Run) (1500m Swim/5k Run) (or just the 5k Run) - Boulder Reservoir - Boulder, Colorado - 6:00 p.m.- 303-642-7917
  

  ---

• 23 - Lake to Lake Triathlon - (1.5k Swim/30M Bike/10k Run) - High School - Loveland, Colorado - 6:30 a.m. - 970-669-6372
• 26 - Aquaman Swim/Run Series #1 - (1M or 0.5M Swim/5k Run) - Cherry Creek State Park - Denver, Colorado - 6:15 p.m. - 303-408-1195

  ---

• 28 - Boulder Stroke & Stride Series #4 - (750m Swim/5k Run) (1500m Swim/5k Run) (or just the 5k Run) - Boulder Reservoir - Boulder, Colorado - 6:00 p.m.- 303-642-7917
  

  ---

• 30 - Lookout Mountain Triathlon - (500m Swim/10M Bike/5k Run) - Mt Vernon Country Club - Golden, Colorado - 6:30 a.m. - 303-642-7917
  

  ---

• 3 - Aquaman Swim/Run Series #2 - (1M or 0.5M Swim/5k Run) - Cherry Creek State Park - Denver, Colorado - 6:15 p.m. - 303-408-1195

  ---

• 5 - Boulder Stroke & Stride Series #5 - (750m Swim/5k Run) (1500m Swim/5k Run) (or just the 5k Run) - Boulder Reservoir - Boulder, Colorado - 6:00 p.m.- 303-642-7917
  

  ---

• 8 - Boulder Peak Triathlon - (1.5k Swim/42k Bike/10k Run) - Boulder Reservoir - Boulder, Colorado - 813-868-7518
• 9 - Dunk & Dash - (800Y Swim/5k Run) (1600Y Swim/5k Run) - Nottingham Lake - Avon, Colorado - 720-309-7518
• 10 - Aquaman Swim/Run Series #3 - (1M or 0.5M Swim/5k Run) - Cherry Creek State Park - Denver, Colorado - 6:15 p.m. - 303-408-1195

  ---

• 12 - Boulder Stroke & Stride Series #6 - (750m Swim/5k Run) (1500m Swim/5k Run) (or just the 5k Run) - Boulder Reservoir - Boulder, Colorado - 6:00 p.m.- 303-642-7917
  

  ---

• 14 - XTerra Beaver Creek - point to point (1M Swim/uphill mtn Bike/5.75M Run) - Nottingham Lake - Avon, Colorado - 9:00 a.m. - 970-845-5293
• 14 - Adventure XStream Race Series - (Paddle/Mtn Bike/Trail Run/Orienteering/Navigation) - Frisco, Colorado - 970-259-7771

  ---

• 15 - Ultimate Direction Evergreen Sprint Triathlon - (750m Swim/12 Mile Bike/5k Run) - Evergreen Lake House - Evergreen, Colorado - 7:00 a.m. - 303-642-7917
  

  ---

• 15 - Tri It High Triathlon/Duathlon - (500m Swim/20k Bike/5k Run) (5k Run/20k Bike/5k Run) - Recreation Center - Leadville, Colorado - 719-486-7484
• 16 - Dunk & Dash - (800Y Swim/5k Run) (1600Y Swim/5k Run) - Nottingham Lake - Avon, Colorado - 720-309-7518
• 17 - Aquaman Swim/Run Series #4 - (1M or 0.5M Swim/5k Run) - Cherry Creek State Park - Denver, Colorado - 6:15 p.m. - 303-408-1195

  ---

• 19 - Boulder Stroke & Stride Series #7 - (750m Swim/5k Run) (1500m Swim/5k Run) (or just the 5k Run) - Boulder Reservoir - Boulder, Colorado - 6:00 p.m.- 303-642-7917
  

  ---

• 21 - State Games of America Triathlon - (750m Swim/13M Bike/5k Run) (kids distances) - Memorial Park - Colorado Springs, Colorado - 7:15 a.m. - 719-634-7333 x1003

  ---

• 22 - Steamboat Sprint Triathlon - (1/5M Swim/12.4M Bike/5k Run) - Steamboat Lake State Park - Steamboat, Colorado - 8:00 a.m. - 303-408-1195
  

  ---

• 23 - Dunk & Dash - (800Y Swim/5k Run) (1600Y Swim/5k Run) - Nottingham Lake - Avon, Colorado - 720-309-7518
• 24 - Aquaman Swim/Run Series #5 - (1M or 0.5M Swim/5k Run) - Cherry Creek State Park - Denver, Colorado - 6:15 p.m. - 303-408-1195

  ---

• 26 - Boulder Stroke & Stride Series #8 - (750m Swim/5k Run) (1500m Swim/5k Run) (or just the 5k Run) - Boulder Reservoir - Boulder, Colorado - 6:00 p.m.- 303-642-7917
  

  ---

• 28 - My Way or the Tri Way Triathlon - Duathlon - Aquathlon - Aquabike - (750m Swim/14M Bike/5k Run) - Aurora Reservoir - Aurora, Colorado - 7:30 a.m. - 303-642-7917
  

  ---

• 29 - Rocky Mountain Triathlon - (800m Swim/20M bike/10k Run) (400m Swim/12M Bike/5k Run) - North Pond Park - Silverthorne, Colorado - 8:00 a.m. - 720-255-5475
• 30 - Dunk & Dash - (800Y Swim/5k Run) (1600Y Swim/5k Run) - Nottingham Lake - Avon, Colorado - 720-309-7518
• 31 - Aquaman Swim/Run Series #6 - (1M or 0.5M Swim/5k Run) - Cherry Creek State Park - Denver, Colorado - 6:15 p.m. - 303-408-1195

---

• 1 - Boulder Stroke & Stride Series #9 - (750m Swim/5k Run) (1500m Swim/5k Run) (or just the 5k Run) - Boulder Reservoir - Boulder, Colorado - 6:00 p.m.- 303-642-7917
  

  ---

• 4 - Indian Peaks XTERRA Triathlon - (1000m Swim/24k Bike/7k Run) - Eldora Mountain Resort - Nederland, Colorado - 303-279-6040
• 4 - Durango Triathlon - (500Y Swim/13M Bike/5k Run) - Community Recreation Center - Durango, Colorado - 8:00 a.m. - 970-375-7300
• 4 - Kids TRY-athlon - (various distances) - Recreation Center - Parker, Colorado - 7:00 a.m. - 303-805-3278
• 5 - Rohto Ironman 70.3 Boulder - 1.2M Swim/56M Bike/13.1M Run) - Boulder Reservoir - Boulder, Colorado - 813-868-5940
• 5 - Tri For The Cure - (500m Swim/10M Bike/5k Run) - Cherry Creek State Park - Denver, Colorado - 7:00 a.m. - 303-430-2969
• 6 - Dunk & Dash - (800Y Swim/5k Run) (1600Y Swim/5k Run) - Nottingham Lake - Avon, Colorado - 720-309-7518

  ---

• 9 - Boulder Stroke & Stride Series #10 - (750m Swim/5k Run) (1500m Swim/5k Run) (or just the 5k Run) - Boulder Reservoir - Boulder, Colorado - 6:00 p.m.- 303-642-7917
  

  ---

• 11 - Splash Mash Dash Triathlon - (0.28M Swim/10M Bike/3.5M Run) (0.62M Swim/20M Bike/6.2M Run) (kids: various distances) - Northbridge Recreation Center - Highlands Ranch, Colorado - 6:00 a.m. - 303-791-3500
• 11 - Fowler Sprint Triathlon - (525Y Swim/8M Bike/4M Run) - Community Pool & Park - Fowler, Colorado - 8:00 a.m. - 719-263-4279

  ---

• 12 - Outdoor Divas Triathlon - (750m Swim/12.4M bike/5k Run) - Union Reservoir - Longmont, Colorado - 303-408-1195
  

  ---

• 18 - Rattlesnake Olympic Triathlon - (1500m Swim/40k Bike/10k Run) - Aurora, Colorado - 720-232-8669

  ---

• 19 - Steamboat Triathlon - (1.5K Swim/40k Bike/10k Run) - Lake Catamount - Steamboat Springs, Colorado - 8:00 a.m. - 303-408-1195
  

  ---

• 18 - Rattlesnake Sprint Triathlon - (500m Swim/12M Bike/5k Run) - Aurora, Colorado - 720-232-8669
• 25 - Iron Girls Triathlon - (0.25M Swim/17.2M Bike/3.1M Run) - Boulder Reservoir - Boulder, Colorado - 7:00 a.m. - 813-868-5940

  ---

• 26 - XTERRA Lory - (0.5M Swim - 10.5M Bike - 8k Run) - Lory State Park - Fort Collins, Colorado - 303-408-1195
  

  ---

• 30 - West Side Duathlon - (5k Run/30k Bike/5k Run) (1.5M Run/15k Bike/5k Run) - Long Lakes Sports Complex - Arvada, Colorado - 7:00 a.m. - 303-642-7917
  

  ---

---

• 1 - Racing Underground Open Water Swim - (1.2M or 2.4M) - Boulder Reservoir - Boulder, Colorado - 6:30 a.m. - 303-642-7917
  

  ---

• 1 - Tenderfoot Mountain Triathlon & Duathlon - (40k Bike/10k Run) (1000m Swim/40k Bike/10k Run) - Salida Hot Springs Aquatic Center - Salida, Colorado - 7:00 a.m. - 719-539-6738
• 2 - Tenderfoot Mountain Kids Triathlon - (various distances) - Salida Hot Springs Aquatic Center - Salida, Colorado - 7:00 a.m. - 719-539-6738

  ---

• 8 - Littlefoot Triathlon - (750m Swim/20k Bike/5k Run) - Bear Creek Lake Park - Morrison, Colorado - 720-289-0036
  

  ---

• 9 - Harvest Moon Long Course Triathlon-Duathlon-Aquabike - (1.2M Swim/56M Bike/13.1M Run) - Aurora Reservoir - Aurora, Colorado - 303-408-1195
  

  ---

• 9 - XTERRA Pueblo - (1000m Swim//15M Bike/4M Run) - Pueblo State Park - Pueblo, Colorado - 9:00 a.m.

  ---

• 15 - Crescent Moon Triathlon - (750m Swim/ 20k Bike/5k Run) - Aurora Reservoir - Aurora, Colorado - 8:00 a.m. - 303-642-7917
  

  ---

• 16 - Bear It All Off Road Triathlon - (750 Swim/13M Bike/2.6M Run) (1500m Swim/24M Bike/5.2M Run) - Bear Creek Lake Park - Lakewood, Colorado - 8:00 a.m. - 303-518-0232

  ---

• 23 - Oktoberfest Triathlon - (800m Swim/12.4M Bike/5k Run) - Union Reservoir - Longmont, Colorado - 303-408-1195
  

  ---

---

• 7 - Desert's Edge Triathlon - (750m Swim/21k Bike/5k Run) (1500m Swim/40k Bike/10k Run) - Highline Lake State Park - Loma, Colorado - 8:00 a.m. - 303-642-7917
  

  ---

Send Calendar Listings, Corrections, and Info Requests to info@racingunderground.com