ATX Solstice Circuit 5K and 10K

Austin Solstice Circuit Challenge

The Fastest Summer Ultramarathon in Texas

July 25 & 26, 2026 | Pace Bend Park, Lake Travis

Set a PR!

Scenic Hill Country Course

Experience the breathtaking beauty of the Texas Hill Country as you run on smooth paved roads winding through majestic oak trees. With Lake Travis as your backdrop, this picturesque route combines natural beauty with the perfect running surface for speed and comfort.

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Set your sights on a personal record at the Austin Solstice Circuit Challenge. This unique event features a perfectly engineered 1.64-mile paved loop with an elevation gain of just 33ft at scenic Pace Bend Park on Lake Travis, designed for speed and performance even in July.

Race Distances

52.7 Mile Race

Loops: 32

Distance: 52.7 mi

Start: 7:00 PM 07/25

50K

Loops: 19

Distance: 31.0 mi

Start: 7:00 PM 07/25

Marathon (USATF Certification code: TX25015LAB)

Loops: 16

Distance: 26.35 mi

Start: 7:00 PM 07/25

25K

Loops: 10

Distance: 15.5 mi

Start: 7:00 PM 07/25; 7:00AM 07/26

10K

Loops: 4

Distance: 6.2 mi

Start: 7:00 PM 07/25;

7:00 AM 07/26

5K

Loops: 2

Distance: 3.1 mi

Start: 7:00 PM 07/25

7:00 AM 07/26

Carpe Diem 60

One Hour. One Sunrise.

Beat the heat.

Seize the morning.

Earn your day.

Start: 6:00 AM 07/26

7:00 AM 07/26

Why Choose This Race?

Fast, PR-Friendly USATF Certified Marathon Course (Boston Qualifier)

Unlike typical Texas summer ultras with brutal heat and technical trails, our smooth asphalt loop with minimal elevation gain creates ideal conditions for record-setting performances. This is a USATF-certified course: Certification code: TX25015LAB.

Evening Start Format

Race as the sun sets and July's magnificent Buck Moon rises over the limestone bluffs. Our strategic evening start times for longer distances mean cooler temperatures when you need it most.

Pacers Allowed

While we won't be providing official pacing groups for the Austin Solstice Circuit Challenge due to our size, we enthusiastically welcome personal pacers for both the Marathon, 50K and 52.7 Mile Solo events. Personal pacers can join Marathon and 50K participants after 8 loops and 52.7 Mile runners after 16 loops (approximately halfway points). Each pacer must pay a $15 fee that covers park entry, administrative costs, and an official pacer bib. Pacers need to sign a waiver and wear their designated "PACER" bib while on course. Runners are responsible for arranging their own pacers, but the loop format makes it particularly convenient for your support crew to join when you need them most. We find this flexibility is especially appreciated by first-time marathoners and ultra runners who benefit from personalized support during the challenging later miles as day turns to evening.

Pickup Information:

Saturday Packet Pickup:

Available from 4:30 PM to 6:30 PM.

Race Day Pickup:

For those unable to attend on Saturday or who prefer to pick up on race day, same-day packet pickup will be available Sunday morning from 5:30 AM to 6:30 AM.

Carpe Diem 60

One Hour. One Sunrise. Start your day with purpose.

Carpe Diem 60 is a 60-minute sunrise endurance challenge on this out-and-back course. At 6:00 AM, you’ll have one hour to cover as much distance as possible with early morning focus. Most Distance Covered Wins

Beat the heat. Seize the morning. Earn your day.

Course Details

The distinctive figure-8 course winds through the breathtaking Hill Country landscape of Pace Bend Park, featuring limestone bluffs, majestic oak trees, and views of Lake Travis. The smooth asphalt surface throughout makes it perfect for both day and night running, with the main loop connecting to a smaller upper loop.

• Surface: 100% smooth, paved asphalt – ideal for consistent pacing

• Elevation: Minimal gain per loop – gentle, predictable terrain

• Loop Length: 1.64 miles in a figure-8 configuration

• Scenery: Limestone bluffs, oak-covered hills, and Lake Travis views

• Aid Station: Access every 1.64 miles at the start/finish hub

• Marking: Fully marked with reflective markers for nighttime visibility

"Whether you're chasing a PR, a qualifying time, or simply want to experience the joy of running fast through a Texas summer night beneath towering oaks and limestone cliffs, the Solstice Circuit Challenge offers a rare opportunity to push your limits under optimal conditions."

Amenities

Aid Station

Fully stocked station at the start/finish hub

Restrooms

Convenient toilet vault facilities

Camping

First-come, first-served sites surrounding the course

Parking

Multiple areas for easy access

Finisher Awards

Medals and custom challenge coins for all finishers

Commemorate your achievement with a premium custom-designed medal featuring Lake Travis. These coins are part of the Race Austin Series: Collector's Challenge, which allows you to exchange three same-tier coins from different Fit Foundation races for a complimentary race entry of the same tier.

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Join Us for an Unforgettable Experience

Race from sunset to stars beneath the Buck Moon on the fastest summer ultra course in the Texas Hill Country.

REGISTER NOW!

Ready to prepare? Check out our comprehensive training guide designed specifically for the Solstice Circuit Challenge.

August 8th, 2025.

This is the culminating event in the Capt'n Karl's Trail Series at one of the best privately owned adventure parks in all of Texas, the amazing Reveille Peak Ranch! This park is located 55 miles northwest of Austin in the historic town of Burnet. The amenities at RPR are first class & we will be taking advantage of this by providing our runners, spectators & volunteers with a series finale party. But first, runners will be treated to unique & spectacular geological formations. Navigating over large rock domes with amazing views, while tackling the most elevation gain of our four venues (3812 ft). This course really has it all….single track, exposure, tree-covered woods, hills & technicality. All to challenge even the most seasoned trail runner.

While every racer will get some cool swag, July 16th is the deadline to get a shirt.

Join us for the annual Summer Sizzler 5k/10k/15k! A fun summer event that is perfect for the whole family.

The fun includes -

• Great Swag - designer shirt & custom medal

• Chip-timing with live results and awards

• Free photos

• Delicious Treats waiting at the finish line

• FREE Kona Ice!

• Plenty of fun!

Grab your friends and family, you are not going to want to miss this one!

Can't make the race? No problem! We offer a virtual race option where you can run anywhere, at any time, and still earn the fun swag!

*Youth-based pricing for the 5k/10k, 12 & Under are only $17!

• 5k/10k/15K registration includes a custom bib, designer shirt, and a custom finisher medal!

• 1 Mile registration is untimed and includes a custom bib, designer shirt, and a custom finisher medal!

• The kid's dash is a fun, untimed dash for our kiddos ages 10 and under. Registration includes a mini bib, youth-sized shirt, and a specifically crafted medal for our kids' dash event! (If your child wants to run the kid's dash, and doesn't want the SWAG, they are welcome to run with us on race day for free!)

*Register by midnight on Thursday, two Thursdays before race day, to guarantee your shirt!

🏁🏅Create a team, or join an existing team during registration. Once 4 people have registered on that team, all team members will be refunded $5, once ten people register another $5 will be refunded for a total of $10!

September 12, 2026.

Get your friends and family, and join in on this close to Austin and San Antonio lake party and trail run! The finish line arch will be as close to the edge of Lake Travis as we can get it (Austin area’s famed lake boasting over 9 miles of shoreline)! So when you finish you can cruise straight into the water to cool off and start your floating post-race party! This means, as the lake rises and falls each year, the distance will possibly slightly change, so we'll add "ish" to each distance...and that's perfect when everything and everyone stays mellow.

We’re incredibly thankful for the support of this race by the Travis County Parks Foundation!

While every racer will get some cool swag, August 18 is the deadline to get a shirt.

During registration, we are collecting $10 for one day of access to the park. If runners are staying for more than one day, they will have to pay additional amounts upon entering the park.

Click Here for Tejas Trails Policies (you really do want to know this stuff)