Rio Colorado Ultra Slam™
Date and time
Thursday, December 31, 2026 · 6:00 PM
Location
Various, Spicewood, TX
Date and time
Thursday, December 31, 2026 · 6:00 PM
Location
Various, Spicewood, TX
Date and time
Thursday, December 31, 2026 · 6:00 PM
Location
Various, Spicewood, TX
Rio Colorado Ultra Slam™
Multiple races. One river. One of the toughest endurance challenges in Texas.
The Rio Colorado Ultra Slam™ is a journey that tracks the spectacular geographical transformation of Texas. Runners trace the lifeblood of the Lone Star State, moving from the rugged granite cliffs of the Hill Country, winding through the sandy loam of the Lost Pines savannah, and culminating in a brutal, beautiful endurance showdown on the edge of the Gulf of Mexico.
From Tow, near the Canyon of the Eagles on Lake Buchanan to the Colorado River's mouth at Matagorda Bay, the river carves a path of approximately 431 to 432 river miles. The Ultra Slam challenges you to conquer this epic expanse on foot, anchored by our pinnacle achievement: a clean, rounded challenge distance of 400 MILES IN ONE YEAR.
Only 50 athletes will be accepted into the Ultra Slam 200, only 25 into the Ultra Slam 400, and a limited roster into the Ultra Slam 150. Once the roster is set, it is set. This is not a participation series. This is a commitment.
2027 SEASON | Races run January 1 through December 31, 2027
Three Ways to Earn It
Ultra Slam 150Complete five qualifying races of at least 50K distance each. Click here for the series leaderboard.Ultra Slam 200Complete four qualifying races of at least 50 miles each. Click here for the series leaderboardUltra Slam 400Complete four qualifying races of at least 100 miles each. Click here for the series leaderboard Note: Backyard ultras count toward the Ultra Slam 200 and 400 tiers only, when you reach the required distance (50+ miles for the 200, 100+ miles for the 400). Backyard ultras do not count toward the Ultra Slam 150, which requires five completed 50K trail races.
Qualifying Races
Choose your required number of races from the following, to be completed within the 2027 calendar year:
50K Tier (Ultra Slam 150)
Austin Solstice Circuit Labor Day Trail Challenge Autumn Harvest Colorado River Run Star of Texas Canyon of the Eagles Lost Pines Bluebonnet Trail
50+ Mile and 100+ Mile Tiers (Ultra Slam 200 and 400)
Austin Solstice Circuit (52 Miler or 12-Hour Solo) Big Bastrop Backyard Ultra Colorado River Run (50 Mile or 100 Mile) Star of Texas 50 Miler Canyon of the Eagles New Year's Trail Challenge The Lost Pines Endurance Fest Matagorda: The Gulf Coast Backyard Ultra Rodeo Trail Run of Austin Backyard Ultra Bluebonnet Trail Run 50 Miler Austin's Backyard Ultra
Entry Fee and Early Bird Pricing
Your Ultra Slam entry is a single bundled fee that covers all your chosen races. Register early to take advantage of our Founding Athlete Early Bird rates.
TierEarly Bird PriceRegular PriceUltra Slam 150$545$595Ultra Slam 200$745$795Ultra Slam 400$1,145$1,195 Payment plans are available at checkout: three monthly installments for any tier. Race swaps are permitted up to 60 days before the event date of the race you are dropping, subject to availability.
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.
What You Get
Entry into all your chosen races Custom Rio Colorado Ultra Slam finisher buckle Series jacket with tier designation Ultra Slam bib number carried across all events Your name on the permanent Rio Colorado Ultra Slam finisher wall
How It Works
Register here and pay the bundled entry fee for your tier. Select your races at checkout (you can adjust up to 60 days before each race). Show up. Finish. Repeat. Receive your finisher buckle upon completion of your tier.
We track your qualifying finishes automatically, and you will receive a confirmation email after each race showing your progress.
Fine Print
The 2027 season runs January 1 through December 31, 2027. All races must be completed within the 2027 calendar year. Backyard ultras must reach the qualifying distance (50 miles for the 200 tier, 100 miles for the 400 tier) to count. Backyard ultras do not count toward the Ultra Slam 150. Refunds are not available once the roster closes. Deferrals may be granted for documented medical reasons at the race director's discretion. Entrants who do not complete the required races receive credit toward individual race finishes but do not earn the Slam buckle or jacket.
SEE YOU ON THE RIVER.
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