TMC Earth Day 5k at the Biosphere 2

Celebrate Earth Day at the TMC Earth Day 5K at the Biosphere 2! Set against the majestic backdrop of the Santa Catalina Mountains, this unique event invites runners and walkers of all ages to explore the hidden backroads of the world-famous Biosphere 2. Whether you are pushing for a personal record or enjoying a scenic family walk, our rolling 3.1-mile course offers stunning desert vistas, culminating in an exciting finish on the iconic Great Lawn, set against the iconic architecture of the Biosphere 2. Turn your Earth Day into an unforgettable outdoor experience—register today to run, explore, and support groundbreaking planetary science!

Event Highlights & Registration Details

• Free souvenir shirt for all registrants with a special add-on commemorative medal for sale, too!
• Scenic 3.1-Mile Course: A hilly route through private Biosphere 2 grounds with panoramic mountain views.
• Adult Registration ($40): Includes official 5K entry, a timed bib with a personalized finisher video, a souvenir shirt (first 750 registrants), post-race snacks, and free adult admission to Biosphere 2.
• Youth Registration ($10): Special pricing for children ages 14 and under includes 5K entry and Biosphere 2 access (shirt not included).
• Spectator & Guest Admission Discount: Race morning spectators are free. Non-running guests can purchase discounted Biosphere 2 admission for just $10 (when purchased before 8:30 AM); children under 12 receive free entry.
  

Exclusive Biosphere 2 Experience
Your race entry unlocks self-guided access to the 3.14-acre living laboratory. Go behind the scenes to discover cutting-edge environmental research—including the Landscape Evolution Observatory—and journey through diverse indoor ecosystems: rainforests, wetlands, savanna grasslands, fog deserts, and a living ocean.

Post-Race Celebration & Cause

• Morning Festival: Stay after crossing the finish line for live music, kids' activities, local food trucks, and post-race refreshments.
• Awards & Recognition: Overall and age-group awards generously provided by The Running Shop.
• Run for the Reefs: Proceeds directly support the Ocean Reef Research Project, advancing critical solutions for growing resilient ocean reefs in a changing climate.