Travelers in the area may encounter delays and should follow recommended detours
Boulder County, Colo. - IRONMAN 70.3 Boulder will return to Boulder County on Saturday, June 13, 2026.
All residents will have access to their homes, but you may encounter delays and should follow recommended detours.
If you are traveling through the area during the event please pay close attention to the Boulder County Sheriff, Colorado State Patrol, and the volunteer traffic marshals who will be helping to ensure safety for riders and travelers alike.
When passing a bicyclist, motorists must allow at least three feet of space between their vehicle and a bicyclist. To pass a bicyclist safely, drivers may cross a double yellow center line when oncoming traffic is clear.
Travel Restrictions
The bike course will active between 7 a.m. and 2 p.m. on Saturday, June 13, and will use the following roads:
CO 119/Diagonal Highway, N. 63rd Street, Monarch Road, Jay Road, US 36/N. Foothills Highway, Hygiene Road, N. 75th Street, N. 73rd Street, and N. 71st Street.
- US 36/28th St. will be closed northbound from Jay Rd. to Hygiene Rd. Through traffic on northbound US 36 from Boulder to Lyons should use CO 119 to Longmont, head north on Hover Rd., then west on CO 66. If heading to Estes Park, use the same route or you may also use CO 119 to Nederland, then north on CO 72 to CO 7, then continue north to Estes Park.
- Northbound local access to Longhorn Road businesses will remain open, access is available via US 36 & Broadway
- CO 119/Diagonal Highway will remain open, one lane of westbound/Boulder bound lanes will be closed from N. 63rd St. to Jay Rd. Expect delays.
- Jay Rd. will be closed to westbound traffic from Diagonal Highway to 28th St.
- N. 75th St./73rd/71st St. will be closed southbound from Hygiene Rd. to Niwot Rd. Niwot Rd. will remain open for local access, expect delays
- St. Vrain Rd. will be closed to through traffic, residents will be allowed to access their homes
- Hygiene Rd. will be closed to through traffic, residents will be allowed to access their homes
- Monarch Rd. will be closed from 55th St. to 71st St. Residents will be allowed to access their homes via. 55th and 63rd Streets.
- 63rd St. will be closed from Diagonal Highway to Niwot Rd. from 7 a.m. until 5 p.m. Residents will be allowed to access their homes from Niwot Rd., but there will be no access to CO 119/Diagonal Highway.
- 51st/55th St. will be closed to through traffic from Niwot Rd. to Jay Rd. Residents will be allowed to access their homes.
Do not try to cross the course. If you need to get from one side or the other use US 36 Southbound or N. 75th St. Northbound, and CO 66 to get around the bike course. Please do not attempt to get across on Hygiene Rd., Niwot Rd., Nelson Rd., St. Vrain Rd., Plateau Rd., or westbound Jay Rd. While those roads will remain open for resident access except for as mentioned above, you will experience longer delays than if you use the loop around the bike course.
View more information on travel impacts on the event website.
Shuttles
All athletes and spectators must take a shuttle on race morning (unless carpooling with a volunteer). There is no alternative method to getting to the venue.
Spectators will have shuttle access to the reservoir from 4 a.m. to 10 a.m. (athletes will have priority) on Saturday June 13. Shuttles will not return spectators and athletes until 6 p.m. on Saturday. Please understand that you will not be able to ride a shuttle into the reservoir after 10 a.m.
Parking/Shuttle Pick-up
- Kyndryl Boulder (Former IBM Building) 6300 Diagonal Hwy Boulder, CO 80301. You must access from CO 119/Diagonal Highway.
Shuttle Drop-off
- Boulder Reservoir, 5565 North 51st St Boulder, CO 80301
Boulder Reservoir Impacts
- Boulder Reservoir will be closed to the public Thursday, June 11 at 11 a.m. – Saturday, June 13.
- No watercraft of any kind will be permitted into the Boulder Reservoir ALL DAY Thursday, June 11 – Saturday, June 13.
Recreational Cycling Impacts
- Recreational cyclists should avoid traveling in the same direction as the riders on the bike course.
Questions Or Concerns?
If you have questions or concerns, please email Boulder70.3@ironman.com. More information can be found at the event website.
You may also contact John Holste, Boulder County Special Events Supervisor at jholste@bouldercounty.gov.
IRONMAN 70.3 Boulder Bike Course Map 2026
IRONMAN 70.3 Boulder Run Course Map 2026
Boulder County wants to ensure that everyone has equal access to our programs, activities, and services. To request an Americans with Disability Act (ADA) accommodation, please email ada@bouldercounty.gov, or call 303-441-1386. If you need help in another language, please email cppfrontdesk@bouldercounty.gov or call 303-441-3930.