Hotels have long used words such as "eco," “green” and “sustainable” to stand out in an increasingly crowded market. However, European regulators are now scrutinizing these words more closely.

On September 9, Britain’s Advertising Standards Authority (ASA) published rulings against Thomas Cook, loveholidays and DialAFlight over travel ads using phrases such as "eco resort," "eco hotel" and "eco-conscious resort."

This ruling arrived less than three weeks before stricter European Union greenwashing rules also take effect on September 27.

UK Regulators Are Already Challenging “Eco” Hotel Claims

A paid Google ad from Thomas Cook promoted the "Sandos Caracol Eco Resort". Thomas Cook argued that Google advertising tools had generated the wording automatically and that “eco” had previously formed part of the hotel’s name.

The ASA still found that consumers were likely to interpret “eco resort” as describing an environmental characteristic or benefit, while the ad failed to explain what that benefit actually was.

Similar rulings against loveholidays and DialAFlight targeted the phrases “eco hotel,” “eco resort” and “eco-conscious resort.”

In the loveholidays case, the company said it was simply reselling third-party hotels and using names supplied by accommodation providers. However, this reasoning did not prevent the ASA from finding the advertising misleading.

The ASA said it identified all three ads through its AI-powered Active Ad Monitoring system, which proactively searches online advertising for potential breaches.

The rulings did not impose fines. However, the United Kingdom’s wider consumer-protection regime gives the Competition and Markets Authority and courts powers to impose penalties of up to 10% of global turnover for breaches of consumer law.

The EU Tightens Green Marketing Rules From September 27

Across the European Union, the Directive (EU) 2024/825 , known as the Empowering Consumers for the Green Transition Directive, was adopted in 2024, but will apply from September 27, 2026 .

The rules add several items to the EU’s blocklist of commercial practices considered unfair in all circumstances. Generic environmental claims such as “environmentally friendly,” “eco-friendly,” “green,” “climate friendly” and “carbon friendly” can be prohibited unless a business can demonstrate recognized excellent environmental performance relevant to the claim.

For hotels, this means that instead of saying a property is “eco-friendly,” it must communicate a measurable environmental achievement that is accurate and substantiated.

The directive also requires qualifications to be presented clearly and prominently rather than being buried somewhere.

Hotels should also review sustainability badges since under the Directive (EU) 2024/825, private sustainability labels generally need to be based on qualifying certification schemes.

Moreover, a claim that a hotel stay has a neutral, reduced, or positive greenhouse-gas impact cannot be based simply on carbon offsetting.

September 27 Is Not The Start Of A Grace Period

EU member states had until March 27, 2026, to transpose the directive. European Commission confirms that “the Directive shall enter into application” from September 27.

From that date, businesses must ensure that consumer-facing environmental claims and sustainability labels comply with the new requirements.

Penalties will be enforced at national level. When imposing a fine, authorities will consider factors such as the seriousness and duration of the violation and whether the business took steps to correct it.

For certain major cross-border infringements, EU consumer-protection rules allow maximum fines of at least 4% of annual turnover in the member states concerned.

In Europe, the word “green” is rapidly becoming less of a marketing shortcut and more of a claim businesses must be prepared to prove.

For hotel companies, the immediate task is clear: audit websites, booking engines, paid search campaigns, social media, OTA listings, sustainability pages, badges and future climate promises.

The lesson from the UK cases is that even a word embedded in a hotel name that is automatically pulled into an advertisement can become an environmental claim in the eyes of regulators.