Denver International Airport is the king of airport Wi-Fi, logging the fastest Wi-Fi speeds among the nation’s 20 busiest airports, internet speed-test company Ookla said Wednesday.

DIA’s speed was — drumroll, please — 61.74 megabits per second! And bonus — it’s free.

The slowest was Hartsfield-Jackson Atlanta International Airport, coming in at a measly 2.71 mbps.

Ookla tested Wi-Fi and mobile service internet speeds during the last three months of 2016. Researchers lauded Denver’s investment in Wi-Fi technology at the airport.

“For the 2016 period analyzed in the article, Denver indeed was the fastest of the 20 busiest airports (based on passenger boardings),” Ookla spokeswoman Adriane Holter said. “It is likely this speed is at least heavily partially due to recent investments. That being said, there are lots of factors that impact internet speed in any given location, so I can’t say definitely that the top spot is totally due to those investments.”

Factors that can slow down wireless speeds include the number of users, walls and other structures, and even the speed of the internet connection to the building.

Improving Wi-Fi at the airport has been a priority for DIA and the airport has invested significantly, said Robert Kastelitz, DIA’s senior vice president for technologies and chief information officer.

Since 2015, DIA has spent about $2.5 million to upgrade all the wireless access points to provide optimal coverage throughout the terminals, Kastelitz said. Last year, it contracted with CenturyLink to add two redundant 10 gigabit links for the whole airport. The airport also uses the latest Wi-Fi technology, 802.11ac, to get more compatible devices connected at faster rates.

“We knew that this was an amenity that people were asking for and expecting now,” DIA spokesman Heath Montgomery said. “We have strategically spent our dollars on this amenity to offer fast and free service.”

The first-place rank wasn’t much of a surprise. Kastelitz said his team is constantly using Ookla to test Wi-Fi speeds at the airport and sees travelers posting their own tests. The fastest speed he’s seen posted was 319.86 mbps.

“We’ve done lab tests here, too. With optimal conditions and brand new devices, our internal speeds have hit 579 to 580 (mbps),” Kastelitz said. “So yes, we know that we’re the fastest.”

Back in 2015, DIA also was ranked as the best U.S. airport for Wi-Fi, based on tests by a mobile data analytics company called Wefi, which is now called TruConnect Communications. In tests between March and May 2015, Wefi put DIA’s Wi-Fi at 4.73 mbps.

Ookla also tested cellular data speeds at DIA, which landed at 12th place out of the 20 busiest airports in the nation. Speeds averaged 16 mbps with AT&T scoring the fastest, at 23.73 mbps.

To see results of the rest of the nation’s airports, view Ookla’s findings at “Which US airport has the fastest internet?”