Boulder-based Outside Interactive Inc., in partnership with Green Disco, released its sustainability impact report from the 2025 Outside Festival and Summit on Wednesday, and the numbers tell an impressive tale about how the company is handling the growing event after year two.

According to the outdoors media company, the report underscores the brand’s commitment to scaling a sustainable and low-emissions event.

The 2025’s Outside Festival saw nearly doubled attendance numbers from the inaugural event in 2024, with measuring the event’s environmental impact still a primary focus for organizers, which resulted in a triple-reduced carbon footprint.

“We are proud of the progress we continue to make across our sustainability indicators year over year,” Robin Thurston, CEO of Outside Interactive Inc. said. “As we scale this event to be the global gathering of the outdoor industry for years to come, our commitment to Colorado’s beloved natural spaces and Outside’s passion for environmentally conscious events remains solid.”

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The report highlighted numbers on plastic reduction, smarter energy use, waste diversion and sustainable transport.

Plastic Reduction

• The festival successfully avoided the use of over 196,000 single-use plastic bottles compared to 21,000 in 2024. Thanks to its souvenir refillable cup program, 15,000 reusable cups were distributed, with fewer than 1% ending up in waste streams.

Smarter Energy Use

• The Outside Festival reported a major reduction in on-site energy consumption. By implementing large-scale battery systems, Outside Festival cut overall fuel use by 95%, dramatically reducing the event’s carbon footprint. These efforts contributed to a threefold decrease in carbon emissions (105.12 metric tons of CO2e) compared to 2024’s numbers.

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Waste Diversion

• In total, the festival kept 25,317 pounds of waste out of landfills, boasting a 36% waste diversion rate, notably above the industry average of 30%.

However, according to Outside, the festival’s waste footprint skyrocketed in 2025, which the company expected, even though they had planned to prevent it more than what actually happened.

“It’s not that we got worse, it was that we put our waste stream under even more scrutiny,” Outside said.

Here are the four key reasons that Outside’s waste diversion rates decreased:

1. Expanded scope of data collection

• Outside expanded its scope of collection from last year to include all of load-in and load-out, where there was no sorting, planning to sort waste during load-in and loud-out next year.

2. New areas of waste collection

• Outside also collected waste from the Film and Ideas section this year – the Denver Public Library and Art Museum – which had their own waste infrastructure, leading to more contamination.

3. More sponsors and more giveaways

• Although Outside saw a clear improvement with food vendors, sponsors still brought in many non-approved items that were destined for landfills and contaminated waste streams.

4. Items from outside the festival

• Many items like diapers, cigarettes, etc. were brought outside the festival grounds and Outside had little control over.

Sustainable Transport

• An estimated 18% of fans walked or cycled, generating zero emissions, while an additional 12% of festivalgoers opted for low-emission transit options like buses, trains, or electric scooters.

One other large impact number Outside also saw from the 2025 festival was the amount of water attendees drank.

“Maybe it was hotter, maybe it was the signage, or something else in the air – but we saw a 9x increase in overall drinking water consumption at the stations,” Outside said. “Over 25,901 gallons of tap water were transformed, eliminating the equivalent of 196,000+ single-use plastic bottles (500ml) from the event site.”

Read the full 2025 Outside Festival impact report:

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Transportation initiatives showed notable progress in 2025, as nearly 30% of attendees chose sustainable travel methods, including walking, biking, buses, and trains. Over 1,000 people biked in daily, taking advantage of the secure bike parking on festival grounds, courtesy of the Colorado Tourism Office.

This data is significant because it demonstrates that sustainable practices can scale successfully, even as attendance grows. The Outside Festival will return to Denver in 2026, with exact dates and location to be announced in late 2025.