TMC Earth Day 5K at Biosphere 2

Sat April 22, 2023 Oracle, AZ 85623 US Directions

TMC Earth Day 5k Run/Walk

$35 7:30AM MST - 10:00AM MST
404 spots left. Price increases after February 28, 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!

2023 News: Registration is now open for the 2023 edition of the TMC Earth Day 5k.

2022 News: Click here for the Run Tucson Race Report.  Click here for age group results from our friends at Roadrunner Race Timing. Click here for overall results

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.

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.  

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

All participants receive the following:

  • souvenir t-shirt, celebrating Earth Day
  • official finisher's time with chip timing
  • free entry to the world-famous Biosphere 2
  • discounted entry to spectators, plus free entry for children
  • post-race snacks and goodies

Age-group and overall awards announced soon

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 Planned Schedule:

6:30-7:15 am Race day registration and packet pick up
7:30 Start time for TMC Earth Day 5k Run/Walk
8:45 Free Kids Dash
9:15 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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