About this Race Series
Rio Colorado Ultra Slam™
Ultra Slam 150
The 50K Tier. Five races. Pure trail. No shortcuts.
The Ultra Slam 150 is the entry to the Rio Colorado series and the purist's path. Five 50K trail races across the 2027 calendar year, each one a full-distance ultramarathon in its own right. No backyard shortcuts. No hybrid formats. Just five hard days on Texas trails, from Hill Country granite to Gulf Coast sand.
How to Earn It: Complete five qualifying races of at least 50K distance each within the 2027 calendar year. Backyard ultras do not count toward the Ultra Slam 150.
Qualifying Races
Select any five of the eight races below. Click any race name to view course details, elevation, aid stations, and registration for that specific event.
Austin Solstice Circuit 50K ›
June, Austin. Longest day of the year, twelve hour window, circuit format.
Labor Day Trail Challenge 50K ›
September, Central Texas. End of summer test of grit and heat management.
Autumn Harvest 50K ›
October, Central Texas. Cooler temps, fast trails, prime ultra season.
Fields of Gold 50K ›
Central Texas. 50K distance, wildflower season, one of the most scenic races on the calendar.
Star of Texas 50K ›
A signature Central Texas ultra. Hills, heat, and heart.
Canyon of the Eagles 50K ›
New Year's Trail Challenge. Start your year on Lake Buchanan, at the headwaters of the Colorado.
Lost Pines 50K ›
Bastrop's iconic pine forest. Sandy loam, singletrack, and shade.
Bluebonnet Trail 50K ›
Spring in Texas. Wildflowers, rolling terrain, one of the most beautiful ultras on the calendar.
2027 SEASON | Races run January 1 through December 31, 2027
Pricing
| Tier | Early Bird Price | Regular Price |
|---|---|---|
| Ultra Slam 150 | $545 | $595 |
Your Ultra Slam 150 entry is a single bundled fee that covers all five of your chosen 50K races. Payment plans are available at checkout: three monthly installments. Race swaps are permitted up to 60 days before the event date of the race you are dropping, subject to availability.
What You Get
- Entry into all five of your chosen 50K races
- Custom Rio Colorado Ultra Slam 150 finisher buckle
- Series jacket with Ultra Slam 150 tier designation
- Ultra Slam bib number carried across all five events
- Your name on the permanent Rio Colorado Ultra Slam finisher wall
FOUNDING ATHLETE PRICING
(Year One Only)
This is the inaugural year of the Rio Colorado Ultra Slam. Founding athletes lock in the lowest price this series will ever offer and get their name on the permanent founders wall at Rio Colorado headquarters.
Register for Ultra Slam 150
Founding athlete pricing available while roster spots remain.
FIVE RACES. ONE RIVER. ONE STATE.
Contact Information
If you have any questions about this race series or its scoring, please use the following email address:
Included Events
Austin Solstice Circuit 52 Miler • 50K • Marathon • 25K • Half-Marathon • 10K • 5K • 12-Hour Solo & Relay
Marathon
Saturday July 25, 2026
Spicewood, TX US
Labor Day Trail Challenge 50K • Marathon • Half Marathon • 10K • 5K • 8-Hour Run/Walk (Solo) • 8-Hour Relay
Marathon
Saturday September 5, 2026
Cedar Creek, TX US
Autumn Harvest 50K • 20-Miler • 10-Miler • 5-Miler • Full • Half • 10K • 5K • Big Bastrop Backyard Ultra (Last Runner & Last Rucker Standing)
Autumn Harvest Marathon
Sunday October 11, 2026
Bastrop, TX US
Fields of Gold 50K • Marathon • Half Marathon • 12 Hour • 1 Hour • 10K • 5K
Gold Marathon
Saturday October 24, 2026
Marble Falls, TX US
Colorado River Run 100 Mile • 50 Mile • 50K • Marathon • Half Marathon • 10K • 5K
Marathon
Saturday November 28, 2026
Marble Falls, TX US
Star of Texas 50 Miler • 50K • Marathon • Half Marathon • 10K • 5K
The Star of Texas Marathon
Sunday December 13, 2026
Spicewood, TX US
Canyon of the Eagles 100: New Year’s Trail Challenge (100K & 50K ULTRA, Marathon ,13.1M RUN & RUCK, 10K & 5K)
Marathon
Friday January 1, 2027
Burnet, TX US
The Lost Pines Endurance Fest
Lost Pines Marathon
Saturday January 16, 2027
Bastrop, TX US
Bluebonnet Trail Run 50 Miler • 50K • Marathon • Half Marathon • 10K • 5K
Marathon
Sunday March 28, 2027
Marble Falls, TX US
