TMC Earth Day 5K at Biosphere 2

  • Date Sat 18th April 2026
  • Time 8:30AM MST
  • Location Oracle, Arizona
  • Price $11.60 - $43.40
  • Races 2 races
  • Distances 5km

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Event summary

Join us for the exciting TMC Earth Day 5K at Biosphere 2 in Oracle, Arizona, on Saturday, April 18, 2026! This vibrant event invites participants of all skill levels to run or walk a scenic 3.1-mile course surrounded by the stunning landscape of the Catalina Mountains. The race will take place entirely on the grounds of the world-famous Biosphere 2, providing a unique opportunity to experience this incredible living laboratory.

Not only will you enjoy a fantastic run, but after crossing the finish line, you can relax with live music, delicious food from local food trucks, and a host of fun activities for the whole family. Registration is just $40, which includes a souvenir shirt, race entry, and free access to the Biosphere 2. There’s also a special rate of $10 for children aged 14 and under that includes race entry and admission.

Don’t miss out on this chance to celebrate Earth Day while supporting the Ocean Reef Research Project. Mark your calendars for April 18, and get ready to make lasting memories at this extraordinary event!

Organiser's Description

MARCH 31 UPDATE: HERE IS THE FIRST PRE-RACE EMAIL [https://conta.cc/3PHNDeD]TO ALL PARTICIPANTS WITH RACE WEEKEND DETAILS:



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.



CLEAR YOUR SCHEDULE AND JOIN US AT THE APRIL 18TH 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.



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.



PRICING: $40 FOR THE $5K INCLUDES RACE ENTRY, SOUVENIR SHIRT, FREE BIOSPHERE 2 ENTRY (SPECIAL PRICE OF $10 FOR CHILDREN 14-AND-UNDER INCLUDES THE 5K RACE AND ENTRY TO BIOSPHERE 2, BUT NO SOUVENIR SHIRT).



ONGOING TOURS OF THE BIOSPHERE 2: EXPLORE A 3.14-ACRE LIVING LABORATORY WHERE CUTTING-EDGE RESEARCH UNFOLDS ACROSS DIVERSE ECOSYSTEMSINCLUDING THE LANDSCAPE EVOLUTION OBSERVATORY.

ALL REGISTRANTS RECEIVE FREE ENTRY TO THE BIOSPHERE 2 INFORMATIVE TOUR OF THE RENOWNED RESEARCH FACILITY, WITH AN EXCLUSIVE PEEK INTO THE INNER WORKINGS OF THE BIOSPHERE 2, A WILD WORLD OF WETLANDS, RAINFORESTS, GRASSLANDS, FOG DESERTS, AND THE BIG BLUE OCEAN. IT'S LIKE A BACKSTAGE PASS TO NATURE'S SUPERSTAR HABITATS!

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 $10 (BEFORE 8:30 AM) AND ALL CHILDREN UNDER 12 ARE FREE.



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. [https://runsignup.com/Race/Donate/AZ/Oracle/Biosphere2EarthRun5k]



WHAT YOU GET:



*

SOUVENIR SHIRT TO FIRST 750 REGISTRANTS

*

TIMED 5K WITH FINISHER'S VIDEO

*

AGE GROUP AND OVERALL AWARDS COURTESY OF THE RUNNING SHOP

*

FREE ENTRY TO THE WORLD-FAMOUS BIOSPHERE 2

*

SNACKS AND DRINKS

*

FOOD TRUCKS WITH YUMMY POST-RACE FOOD FOR PURCHASE

*

CHILDREN'S ACTIVITIES



SCHEDULE

THURSDAY, APRIL 16
4:00 - 6:00 PM PACKET PICKUP AND IN-PERSON REGISTRATION AT THE RUNNING SHOP, 3055 NORTH CAMPBELL, TUCSON
T-SHIRTS TO THE FIRST 750 REGISTERED, SIZING AND STYLE ON A FIRST-COME, FIRST-SERVED BASIS.
YES: YOU CAN PICK UP THE NUMBER/SHIRT OF OTHER PEOPLE
YES: YOU CAN SHOP FOR COOL GOODIES AT THE RUNNING SHOP.
YES: IT MAY BE CROWDED, SO PLEASE BE NICE TO EVERYONE
YES: BE SURE TO TAKE PINS AND PIN YOUR NUMBER ON THE FRONT OF YOUR RACING SHIRT.


SATURDAY, APRIL 18 AT BIOSPHERE 2, 32540 S BIOSPHERE RD, ORACLE, AZ 85739
PLEASE CONSIDER CARPOOLING. PLEASE PARK IN THE MAIN PARKING LOT AT THE BIOSPHERE 2. PLEASE FOLLOW THE DIRECTIONS OF THE BIOSPHERE 2 STAFF ON HAND.

7:15-8:15 AM RACE DAY REGISTRATION AND PACKET PICK UP IN THE PARKING LOT BY THE FRONT ENTRANCE AT THE BIOSPHERE 2. PICK UP YOUR RACE SHIRT AND COLORFUL RACE BIB NUMBER.
8:30 AM START TIME FOR TMC EARTH DAY 5K RUN/WALK
8:30 OR SO: FOOD TRUCKS, WITH SNACKS AND DRINKS AVAILABLE FOR PURCHASE
9:45 AM FREE KIDS DASH ON THE GREAT LAWN
10:00 AM AWARDS, COURTESY OF THE RUNNING SHOP. REMAINING SHIRTS AVAILABLE TO LATE REGISTRANTS, FIRST-COME, FIRST-SERVED.
10:15 EVENT WRAP-UP
TOUR THE BIOSPHERE 2: 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 $10 (BEFORE 8:30 AM) AND ALL CHILDREN UNDER 12 ARE FREE.

POST-RACE: IF YOU CAN'T MAKE THE RACE WEEKEND ACTIVITIES, PLEASE NOTE THAT ANY REMAINING SHIRTS WILL BE BROUGHT TO THE RUNNING SHOP AND AVAILABLE FOR PICKUP BETWEEN APRIL 21 - MAY 15. TO GET THE SIZE YOU WANT, PICK UP YOUR SHIRT IN ADVANCE.



NICE WORDS FROM 2024 RUNNER DALE: ITS IMPORTANT TO ME TO THANK THE PEOPLE WHO HELP MAKE TUCSON THE AWESOME COMMUNITY IT IS! SATURDAYS EARTH DAY WAS FABULOUS! IVE BEEN FORTUNATE TO ATTEND ALL THE RACES YOUVE HAD OUT THERE! JUST THE VIEW AND SPACE IS INCREDIBLE AND WHAT A GIFT TO BE ABLE TO STRUGGLE UP THE HILLS WHILE TAKING IT ALL IN! THANK YOU SO MUCH FOR ALL YOU AND YOUR STAFF/TEAM DO.

NICE WORDS FROM 2024 RUNNER LOUISE: WOW!! ARE YOU GUYS EFFICIENT OR WHAT? THANKS SO MUCH FOR THE QUICK TURNAROUND WITH RESULTS AND, AGAIN, FOR ORGANIZING AND RUNNING A GREAT EVENT. THE WATER STOP WAS ESPECIALLY APPRECIATED ON A HOT DAY. (AND EVEN IF WE WERE RUNNING SHORT OF TIME, THE ANNOUNCER WAS FUNNY AND ADDED AN ENJOYABLE ELEMENT TO ANNOUNCING THE WINNERS.)



BRING THE KIDS! SPECIAL $10 PRICE FOR CHILDREN 14-AND-UNDER IN THE 5K: INCLUDES RACE NUMBER, TIMING, AND ENTRY TO BIOSPHERE 2, BUT NO T-SHIRT.

RUNNING STROLLERS ARE WELCOME, BUT BE MINDFUL OF THE STEEP HILLS AND BE SURE TO HAVE THE LEASH ATTACHED!

AFTER THE 5K, THE LITTLE ONES CAN ENJOY THE FREE KID'S DASH & KID'S ZONE ACTIVITIES.

DO GOOD! THIS 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 TIA@RUNTUCSON.NET.

THIS EVENT IS A PARTNERSHIP BETWEEN RUN TUCSON & THE BIOSPHERE 2, THE UNIVERSITY OF ARIZONA

QUESTIONS? CONTACT RACE DIRECTOR RANDY ACCETTA AT RANDY@RUNTUCSON.NET.

Races

  • TMC Earth Day 5k Run/Walk

    Incl. $3.40 Fee & Souvenir T-Shirt

    Sat 18th April 2026 (8:30AM MST)

    $43.40

    5k Run or Walk on the grounds of the Biosphere 2
  • Children's 5k Discount

    Incl. $1.60 Fee

    Sat 18th April 2026 (8:30AM MST)

    $11.60

    Please note that all children will run in the same 5k race as everyone else -- this is not a separate event, but it is just a way to make this event more affordable for families. $10 price for children 14-and-under: includes race number, timing, and entry to Biosphere 2, but no t-shirt. If you want your child to receive a race shirt, please enter them in the regular 5k event.

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Location

32540 S. Biosphere Road, Oracle, 85623, AZ, United States

Who's In

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Donna M Evans

Marissa Renee Edmondson

Mykaela Sanchez

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