Newest hotel perk: Portable Wi-Fi (and it's free!)

Here's an amenity you won't find at many hotels: Wi-Fi to go.

All 19 Room Mate hotels in Europe and the Americas -- including three in the USA -- will begin offering complimentary portable Wi-Fi.

The "WiMate Total Wi-Fi" program will mean that guests will be able to get internet access anywhere at their destination without having to pay data or roaming charges.

Guests can request a mini router when they make a reservation through the Room Mate website or at the front desk upon arrival. Up to five devices including mobile phones, tablets and laptops can be powered by the router. Guests will get 100 MB of high-speed Internet.

Hotels typically charge for Wi-Fi. Even if they offer it for free, they often have a fee for high-speed Internet. Offering portable Wi-Fi is an unusual amenity.

Room Mate has been trying out the service at its hotels in Spain since 2014. Room Mate hotels are located in 12 cities, including Miami and New York.

"Posting on social media, referencing mobile maps and sharing travel moments with family and friends has become a huge part of the travel experience," says Room Mate CEO and founder Enrique Sarasola. "We're proud to be the first hotel group to offer free WiFi in not just our hotels, but throughout entire cities, so our guests can better enjoy their trips."

Sarasola says reservations picked up at the hotels after he introduced the amenity.

"When we did a survey with our clients, they said the most important thing was the Wi-Fi," Sarasola says. "It's helped our direct reservations a lot. It's been a good way of making revenues."

In an online survey by Skift and American Express conducted last summer, 35.2% of 825 travelers said free Wi-Fi was the No. 1 amenity they looked for when choosing a hotel while on the road for business.

"This offers a great way for the hotel to eliminate one of the greatest headaches associated with travel – connectivity," says Robert Cole, founder of RockCheetah, a travel consulting firm. "This allows one to seamlessly continue one's digital lifestyle while traveling. Paying for each device logging into a hotel Wi-Fi network, paying premiums for decent speed or even being locked into using the hotel Wi-FI only in the room or public areas is a huge dissatisfier for hotel guests."