TMC Earth Day 5K at Biosphere 2

🌍 Race Overview

Looking for a way to celebrate Earth Day? Join us at Biosphere 2 for a 5k run and walk, entirely on the grounds of the famed facility. Whether you're a seasoned athlete or just looking for a fun way to get some exercise, you're sure to enjoy yourself at the world-famous Biosphere 2.

📅 Date & Location

• Date: April 18, 2026
• Location: 32540 S. Biosphere Road, Oracle, AZ
• Registration: Sign up here

🏃 Course Description

Clear your schedule and join us at the TMC Earth Day 5k, where you can walk or run the hidden Biosphere 2 backroads, nestled at the base of the majestic Catalina Mountains, north of Tucson. The rolling 3.1 mile course is perfect for racing and walking, with gorgeous desert and mountain views and a start and finish on the beautiful Great Lawn.

🎉 Post-Race Activities

After the 5k, you can relax, listen to music, snag some food, and enjoy other fun activities, so make sure to stick around to socialize and have some fun.

• Free entry: Entry to the Biosphere 2 informative tour of the renowned research facility.
• Exclusive peek: Into the inner workings of the Biosphere 2 – from wetlands to rainforests.

🌊 Fundraising Efforts

The TMC Earth Day 5k is raising funds for the Ocean Reef research project, learning how to grow ocean reefs in a changing climate. See details and donate here.

👕 Event Highlights

• Souvenir shirt: To first 600 registrants
• Timed 5k: With finisher's video
• Awards: Age group and overall awards courtesy of The Running Shop
• Food options: Food trucks with yummy post-race food for purchase

🕒 Schedule

• Packet Pickup: April 17, 4:00 - 6:00 pm at The Running Shop, Tucson
• Race Day Registration: April 18, 7:15-8:15 am at Biosphere 2
• Start Time: 8:30 am for TMC Earth Day 5k Run/Walk
• Awards: 10:00 am, courtesy of The Running Shop

🌟 Family Fun

Bring the Kids! Strollers are allowed at this child-friendly event, with a free Kid's Dash & Kid's Zone. Special $5 price for children 14-and-under includes race number, timing, and entry to Biosphere 2, but no t-shirt.

🌱 Important Details

• Terrain: Mostly pavement, with a brief dirt section
• Difficulty: Hilly in sections
• Pets Allowed: No
• Weather: 50's - 70's

💬 Contact Information

For training advice, contact RRCA-certified running coach Tia Accetta at tia@runtucson.net.

Questions? Contact Race Director Randy Accetta at randy@runtucson.net.