TMC Earth Day 5K at Biosphere 2

Sat April 22, 2023 Oracle, AZ 85623 US Directions


TMC Earth Day 5k Run/Walk

$40 7:30AM MST - 10:00AM MST
256 spots left. Registration ends April 20, 2023 at 11:59pm MST

Event Website

Additional event information can be found at


32540 S. Biosphere Road
Oracle, AZ US 85623


Run the Desert . . . then visit a rain forest, view an ocean reef, and wander through savanna grass lands . . . all in one day!

Join us at the 2nd Annual TMC Earth Day 5k, where you can walk or run the hidden backroads of the world-famous Biosphere 2, nestled at the base of the majestic Catalina Mountains, north of Tucson. The rolling 3.1 mile course offers gorgeous desert and mountain views, with start and finish on the Biosphere 2 Lawn.  

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. 

Limited to 500 Registrants -- what you get:

  • Souvenir race shirt in soft cotton feel
  • Commemorative race medal, made with recycled materials 
  • 15% discount to Oracle's spectacular ARIZONA ZIPLINE ADVENTURES
  • Staycation prices at iconic Westward Look Resort
  • Free entry to the world-famous Biosphere 2
  • Snacks and drinks
  • Food trucks 
  • COX Conserves special festivities planned

Click here for the Damion Alexander photos.  Click here for the video Damion put together. Click here for the KGUN Morning Blend pre-race interview about the TMC Earth Day 5k at the Biosphere 2.

Don't miss this chance to visit the earth's entire ecosystem under one roof while celebrating Earth Day.

Bring the Kids! Strollers are allowed at this child-friendly event, with a free Kid's Dash & Kid's Zone

Do Good! This inaugural event raises funds for the world-renowned Biosphere 2's Ocean Reef Lab. 

Terrain: mostly pavement, with a brief dirt section

Difficulty: hilly in sections

Weather: 50's - 70's

Differently Abled: Yes, be mindful of hills and dirt road

Pets Allowed: No

Want Training Advice? Contact RRCA-certified running coach Tia Accetta at 

Saturday, April 22, 2023 Updated Schedule:

7:15-8:15 am Race day registration and packet pick up
8:30 Start time for TMC Earth Day 5k Run/Walk
9:30 Free Kids Dash
9:45 or so: Awards
Ongoing: All registrants can visit Biosphere2 on their own -- no need for a formal tour!

All non-running guests can purchase Biosphere 2 admission for the discounted rate of $11 (before 8:30 am) and all children under 12 are free.

This event is a partnership between Run Tucson & the Biosphere 2, the University of Arizona

Questions? Contact Race Director Randy Accetta at  

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